Title of Invention

"A RECOMBINANT ANTIBODY OR A SINGLE CHAIN FV FRAGMENT FOR RECOGNIZING EPITOPES EXPRESSED IN IOR C2 ANTIGEN "

Abstract The invention relates to the obtention of novel recombinant antibodies from murine antibody IOR C5 produced by the hybridoma deposited with the ECCC 97061101 according to the Budapest Treaty. Said recombinant antibodies were obtained using recombinant DNA technology and are characterized in that they recognize antigen ior C2. The recombinant antibodies are specifically chimeric antibody, humanized antibody, and single chain Fv fragment. The chimeric antibody contains the variable domains of the murine immunoglobuiine and the constant regions of the human immunoglobuiine and has been specifically modified in the murine frameworks regions (FRs) and within the latter, in those areas that may result in an antigenic site for cells T. the Fv fragment contains the variable domains of murine immunoglobuiine. The invention also relates to the utilization of recombinant antibodies derived from murine antibody ior C5 in the diagnosis and therapy of colorectal tumors, the metastasis thereof and recurrences.
Full Text ANTIBODIES AND FV FRAGMENT RECOGNIZING ANTIGEN IOR C2.
FIELD OF THE INVENTION
This invention is related to the field of the biotechnology and in particular with new
recombinant antibodies obtained using genetic engineering technology, specifically
with a chimeric antibody, a humanized antibody and a single chain Fv fragment
obtained from murine IOR C5 antibody, which recognize epitopes expressed in for C2
antigen which has been characterised as glycoprotein complex which is expressed in
normal and malignant colorectal cells.
BACKGROUND OF THE INVENTION
They have been tested different forms of colorectal carcinoma treatment, however up
to day the surgery it has been the only curative way. The surgery has allowed
reaching higher percents of survival, when the detection of the tumour is in an early
stage, but unfortunately the most cases are diagnosticated when the tumour has
metastized.
In this moment, the strategy to increase survival includes the diagnosis, the
therapeutic and epidemiology, in stages wherein it has not been produced the
dissemination of the disease to external layers of the organs and the tumour is still
surgically curable. In the way, the knowledge of epidemiological factors as well as the
development of new therapeutically methods will help to increase the survival.
The use of monoclonal antibodies (Mabs) or their fragments, labelled with radioactive
isotopes for the detection of cancer through immunogammagraphic methods, has
been used in the last years. The Mabs have shown potential to be used as carriers of
radioisotopes and to be targeted to the associated tumour antigens.
Some of the radiolabelled antibodies have been used to detect tumours associated
with carcinoembrionary antigens (CEA). The antibodies against CEA, labelled with I-
131 or 1-125 are used to detect tumours producing CEA or associated with this
marker (Patents US No. 3 663 684, US No. 3 867 363 y US No. 3 927 193). Also,
Mabs can be labelled with Tc-99m to get molecules for "in vivo" diagnosis.
The development of the hybridoma antibody technique by Kohler and Milstein
revolutionised the discipline of immunochemistry and provided a new family of
reagents with potential applications in the research and clinical diagnosis of diseases
(Kohler G; Milstein C. (1975) Nature 256, 495-497). These antibodies have not
shown strong therapeutic efficacy, while it has become routine to produce mouse
monoclonal antibodies (mAbs) for use in basic research and clinical diagnosis, it has
been difficult to use these for "in vivo" immunotherapy, because they have reduced
half life in humans, poor recognition of mouse antibodies effector domains by the
human immune system and also because foreign immunoglobulins can elicit an
antiglobulin response (HAMA response) that may interfere with therapy.
The development of the genetic engineering has revolutionised the ability to
genetically manipulate antibody genes and then to produce mAbs having decreased
or eliminated antigenicity and enhanced desired effector functions, when these
antibodies are used in the treatment or diagnosis of some pathologies. These
manipulations have provided an alternative where a murine mAb can be converted to
a predominantly human form with the same antigen binding properties (Morrison S. L;
et al 1984, P.N.A.S. USA, 81,6851-6855).
Recently they have been developed some methods in order to humanise murine or
rat antibodies and decrease xenogenic response against foreign proteins when they
are used in humans.
One of the first intents to reduce antigenicity, has been by producing "chimeric"
antibodies. In these molecules, the variable domains were inserted into human
frameworks, in this way not only it can be reached the decrease of the
immunogenicity but also the improvement of effector functions, because they are
humans and therefore recognised by the immune system (Morrison S. L et al (1984)
P.N.A.S, USA 81, 6851-6855). These chimeric molecules retain the recognition of the
original antigen and its constant region is not immunogenic, although the
immunogenicity against murine variable region is retained.
Other -authors have attempted to build rodent antigens binding sites directly into
human antibodies by transplanting only the antigen binding site, rather than the entire
variable domain, from a murine antibody (Jones P.T et al (1986) Nature 321, 522-
524, Verhoeyen M et al (1988) Science 239, 1534-1536). They have been developed
some applications of this method by Rietchmann (Rietchmann L. et al (1988) Nature
332, 323-327; Quee C. et al (1989) P.N.A.S USA 86,10029-10033), however other
authors have worked with reshaped antibodies, which included some murine
residues in human FRs in order to recover the affinity for the original antigen
(Tempest.P.R (1991) Biotechnology 9, 266-272).
Mateo et al. (US Patent Number US 5712120) described a procedure to reduce
immunogenicity of the murine antibodies. In this procedure, the modifications are
restricted to the variable domains and specifically to the murine frameworks of the
chimeric antibodies. Even more, these modifications are only carried out in the FRs
regions with amphipatic helix structure, therefore are potential epitopes recognised
by T cells. The method proposes to substitute the murine residues inside the
amphipatic regions, by the amino acids in the same positions in the human
immunoglobulines, of course the amino acids involved in the tridimentional structure
of the binding site, it means Vernier's zone, canonical structures of the CDRs and the
amino acid of the inter-phase between light and heavy chain are excluded.
The antibody modified by the method described by Mateo et al, retains the capacity
of the recognition and binding to the antigen, that recognised the original antibody
and it results less immunogenic because of this it is got an increase of the
therapeutic efficacy. Through this procedure only few mutations are necessary to
obtain modified antibodies that shown reduced immunogenicity compared with
chimeric antibodies.
The IOR C5 murine monoclonal antibody (patent application WO 97/33916) is an
lgG1 isotype, obtained from immunisation of Balb/c with SW1116 cells (colorectal
adenocarcinoma), recognised an antigen expressed preferentially in the surface and
cytoplasm of the malignant and normal colorectal cells. This antibody does not
recognise neither CEA, Lewis a, Lewis b, asialylated Lewis, membranes of normal
mononuclear cells antigens nor red globules (Vazquez A. M. et al, Hybridoma 11,
pag. 245-256, 1992).
Western blotting studies using SW1116 membranes extract showed that this
antibody recognized a glycoprotein complex which was denominated ior C2, with two
molecular weight forms (145 and 190 Kda) (Vazquez A. M. et al, Year Immunol.
Basel, Karger, vol. 7, pag. 137-145, 1993).
Also it is known from the state of the art that using genetic engineering techniques,
recombinant fragments can be constructed from monoclonal antibodies. There are
many reports validating the use of different antibody fragments in the "in vivo"
diagnosis and the therapeutic of the diseases.
Ira Pastan et al. (EP 0796334 A1) describes the construction of single chain Fv
fragments, using variables regions of antibodies that specifically recognised
carbohydrates related with Lewis Y antigen. Using these fragments, he developed a
method to detect cells bearing this antigen. Also, he gives evidences of the inhibitor
effect of these fragments on cells bearing the antigen.
SUMMERY OF THE INVENTIONS
This invention is related to recombinant antibodies obtained using genetic engineering technology, specifically with a chimeric antibody, a humanized antibody engineering technology, specifically with a chimeric antibody IOR C5 antibody, produced by the hybridoma of the same name deposited in correspondence with the Budapest Treaty under accession number ECCC 97061101 with European Collection of Cell Cultures, on June 11, 1997. This antibody recognizes epitopes expressed in ior C2 antigen, which is a glycoprotein complex that it is expressed in normal and malignant colorectal cells.

STATEMENT OF THE INVENTION:
Accordingly, the present invention relates to a recombinant antibody or a single chain Fv fragment derived from murine monoclonal antibody IOR C5 or a mutant thereof expressed by a hybridomas deposited as ECCC 97061101, wherein the antibody or Fv Fragment comprises CDR regions and framework regions in light and heavy chains.

DETAILED DESCRIPTION OF THE INVENTION
cDNA Synthesis and Gene Amplification of the variable region of murine C5.
Cytoplasmic RNA was extracted from about 106 hybridoma cells of the monoclonal antibody C5 (Vazquez A.M. et al. Year Immunol, Basel, Karger, vol 7, pag. 137-145, 1993). The method used to extract RNA was described by Faloro et al (Faloro,J.,Treisman,R.Iand Kemen.R. (1989). Methods in Enzymology 65:718-749). The cDNA synthesis reaction consisted of 5 ug RNA, obtained with 25 pmoles of the designed primers to hybridise in the beginning of the constant region of murine lgG1, and in the murine constant kappa region for the light chain, 2.5 mM each of deoxinucleotide (dNTPs), 50 mM Tris-Hcl pH 7.5, 75 mM KCI, 10 mM DTT, 8 mM MgCl2 and 15 u of ribonuclease inhibitor (RNA guard, Pharmacia) in a total volume of 50 µl. Samples were heated at 70°C, for 10 min and slowly cooled to 37°C over a period of 30 min. Then, 100 units reverse transcriptase were added and the
incubation at 42°C continued for 1 hour.
The variable regions of light chain (VK) and heavy chain VH) were amplified using
Polymerase Chain Reaction (PCR). Briefly, 5 µI CDNA of VH or VK were mixed with
25 pmoles of specific primers, 2.5 mM each of dNTP, 5 µI buffer 10X for the enzyme
i DNA polymerase and 1 unit of this enzyme. Samples were subjected to 25 thermal
cycles at 94°C, 30sec; 50°C, 30sec; 72°C, 1 min; and a last incubation for 5 min at
72 °C.
Cloning and Sequencing of Amplified cDNA.
The purified VH and VK cDNA were cloned into TA vector (TA Cloning kit. Promega, USA). Clones were sequenced by the dideoxy method using T7 DNA Pol (Pharmacia, Sweden).

Construction of chimeric genes.
The light and heavy chains variable regions were obtained by enzyme restrictions
from TA vectors and cloned into expression vectors (Coloma M.J. et al., Journal of
Immunological Methods, 152, 89-104, 1992).
The VH genes were cut from TA vector by EcoRV and Nhel digestion, and cloned in
PAH 4604 expression vector, an human constant lgG1 is included and histidinol
resistance gene.
The resultant construction is C5VH-PAH4604. The VK genes were cut from TA
EcoRV and Sail digestion and cloned in PAG4622. This vector contains resistance to
the gpt and used kappa human constant region. The resultant construction is C5VKPAG4622.
Chimeric antibody expression.
NSO cells were electroporated with 10 fig of C5VH-PAH4604 and 10 ug of C5VKPAG4622
and linearized by digestion with Pvul. The DMAs were mixed together,
ethanol precipitated and dissolved in 25 jil water. Approximately 107 NSO cells were
grown to semiconfluency, harvested by centrifugation and resuspended in 0.5 ml
DMEN together with the digested DNA in an electroporation cuvette. After 5 minutes
on ice, the cells were given a pulse of 170 volts and 960 jj.F) and left in ice for a
further 30 minutes. The cells were then put into 20 ml DMEN plus 10% foetal calf
serum and allowed recovering for 48 hours. At this time the cells were distributed into
a 96 -well plate and selective medium applied (DMEN, 10% foetal calf serum, 0,8
ng/ml mycophenolic acid, 250 (ig/ml xanthine). Transfected clones were visible with
the naked eyes 10 days later.
The presence of the human antibody in the medium of wells containing transfected
clones was measured by ELISA. Microtiter plate wells were coated with goat antihuman
(gamma chain specific, After washing with PBST (phosphate buffered saline
containing 0.02% Tween 20, pH 7.5), 100 ±il of culture medium from the wells
containing transfectants was added to each microtitter well for 1 hour at 37°C. The
wells were washed with PBST and the conjugated goat anti- human Kappa, light
chain specific were added and incubated at room temperature for one hour. The
wells were then washed with PBST and substrate buffer containing dietanolamine
added. After 30 minutes the absorbency at 405 nm was measured.
Construction of humanised IOR C5h by T epitopes humanisation.
Prediction of T epitopes.
The variable region sequences of IOR C5 were analysed using AMPHI program,
which predicts segments of the sequences 7 or 11 amino acids in length with an
amphipatic helix, which are related with T immunogenicity. Also it was used SOHHA
program which predicts hydrophobic helix (Elliot et al. J. Immunol. 138: 2949-2952,
(1987). These algorithms predict fragments related with T epitopes presentation in
the light and heavy variable regions of the IOR C5.
Analysis of homology of variable regions.
The variable domains of IOR C5 are compared with those corresponding human
variable domains, to identify the most homological human sequence with murine
molecule. The human sequence databases used were reported in Gene Bank and
EMBL, both of them available in Internet. The comparison was made by an
automated-computerised method, PC-DOS HIBIO PROSIS 06-00, Hitachi.
Analysis for immunogenicity reduction.
The essence of this method lies in reducing the immunogenicity by humanisation of
the possible T cell epitopes, with only few mutations in the FRs, specifically in the
amphipatic helix, excluded the positions involved with the tridimentional structure of
the binding site.
In this method it is compared VH and VK regions of the murine immunoglobuline,
with the most homological human immunoglobuline sequence and it could be
possible to identify the different residues between murine and human sequences,
only inside the amphipatic regions, within the FRs zone (Kabat E.(1991) Sequences
of proteins of immunological interest, Fifth Edition, National Institute of Health), only
these murine residues will be mutated by those of the human sequence at the same
position.
Thcjse residues in the mouse framework responsible for the canonical structures or
those involved in the Vernier zone can not be mutate, because they could have a
significant effect on the tertiary structure and to affect the binding site. Additional
information about the substitutions in the tertiary structure, could be obtain, doing a
tridimensional molecular model of the variable regions.
Cloning and Expression of humanised IOR C5 antibody into NSO cells.
After doing PCR overlapping to get mutations and humanised VH and VK, the
obtained genetic construction corresponding to IOR C5 by humanisation of T cell
epitopes, were cloned into expression vectors in a similar way as used for the
expression of the chimeric antibody, yielding the following plasmids: CSVkhu-
PAG4622 and C5Vhhu-PAH4604. The transfection of these genes into NSO cells
was done in exactly the same conditions that we previously described for the
chimeric antibody.
Obtainment of single chain Fv fragment. Construction and expression of the
scFv.
The strategy includes a first amplification using PCR, which modify VH and VL
sequences, including the endonucleases restriction sites to clone in the expression
vectors. The amplification used designed oligonucleotides on the exact sequence.
After amplifying, the variable regions are purified and digested with the corresponding
restriction enzymes. The DMA fragments are purified and ligated to the expression
vectors. Later, these genetic constructions are expressed in E. coli, following
conventional methods.
In the extraction process of the protein from the producer cells, a rupture process by
ultrasound is doing, and it is possible to separate the soluble and insoluble fractions
combining SDS polyacrylamide electrophoresis gels, nitro-cellulose transfer and
western blot.
Partial purification of the protein is carried out by a process which includes: (1)
separation of the soluble and insoluble material by ultrasound and centrifugation, (2)
Wash in low molarities of urea and solubilization in high concentrations of urea. From
solubilized material, to purify the protein by affinity chromatography to metals ions.
Later, the protein is renaturalised against buffer.
Examples
Example 1. Obtainment of the Chimeric monoclonal antibody.
The VH and VK cDNAs were obtained from RNA extracted from the hybridoma
producing the monoclonal antibody IOR C5 using reversp transcriptase enzyme. The
specific primers used were:
For VH:
5'AGGTCTAGAA(CT)CTCCACACACAGG(AG)(AG)CCAGTGGATAGAC3'
For VK:
5'GCGTCTAGAACTGGATGGTGGGAAGATGG 3'
The ADNc of the chains VH and VK were amplified using polymerase chain reaction
(PCR) with Taq polymerase enzyme, and using specific primers ECORV/NHEI
restriction site for VH and ECORV/SALI for VK. The specific primers used were:
ForVH:
Oligonucleotide 1:
5'GGGGATATCCACCATGGCTGTCTTGGGGCTGCTCTTCT3'
Oligonucleotide 2:
5 TGGGTCGAC(AT)GATGGGG(GC)TGTTGTGCTAGCTGAGGAGAC 3'
ForVK:
Oligonucleotide 1:
5'GGGGATATCCACCATGAGG(GT)CCCC(AT)(GA)CTCAG(CT)T(CT)3'
Oligonucleotide 2:
5'AGCGTCGACTTACGTTT(TG)ATTTCCA(GA)CTT(GT)GTCCC3'
The PCR products were cloned in TA vector (TA cloning kit, Invitrogen). Twelve
independent clones were sequenced by dideoxy method using T7 DNA Pol
(Pharmacia). The VH and VK sequences have high relation with the sub-group 2 of
Kabat.
Then, VH chain was digested ECORV/NHEI and VK, ECORV/SALI, and cloned in
PAH4604 and PAG4622 for VH and VK respectively. These vectors were donated by
Sherie Morrison (UCLA, California, USA), and they are used for the
immunoglobulines expression in mammalian cells. The PAH 4604 vector has
included human constant region lgG1 and the PAG 4622 has human Ck (Novel
vectors for the expression of antibody molecules using variable regions generated by
polymerase chain reaction., M. Josefina Coloma et al, Journal of Inmunological
Methods, 152 (1992), 89-104) The resultant constructions after clonig IOR C5
regions were VHC5-PAH4604 and VKC5-PAG4622.
NSO cells were electroporated with 10 ug of the chimeric vector C5VH-PAH4604 and
10 ug of C5VK-PAG4622 and linearized by digestion with Pvul. The DNAs were
mixed together, ethanol precipitated and dissolved in 25 ul water. Approximately 107
NSO cells were grown to semi-confluence, harvested by centrifugation and
resuspended in 0.5 ml DMEN together with the digested DNA in an electroporation
cuvette. After 5 minutes on ice, the cells were given a pulse of 170 volts and 960 uF
and left in ice for a further 30 minutes. The cells were then put into 20 ml DMEN plus
10% foetal calf serum and allowed to recover for 48 hours. At this time the cells were
distributed into a 96 -well plates and selective medium applied (DMEN, 10% foetal
calf serum, 10mM histidinol). Transfected clones were visible with the naked eyes 10
days later.
The presence of chimeric antibody in the medium of wells containing transfected
clones was measured by ELISA. Microtiter plate wells were coated with goat antihuman
(gamma chain specific, Sara lab). After washing with PBST (phosphate
buffered saline containing 0.02% Tween 20, pH 7.5), 20 ul of culture medium from
the wells containing transfectants were added to each microtitter well for 1 hour at
37°C. The wells were washed with PBST and alkaline phosphatase conjugated goat
anti- human Kappa, light chain specific were added and incubated at room
temperature for one hour. The wells were then washed with PBST and substrate
buffer containing dietanolamine added. After 30 minutes the absorbance at 405 nm
was measured.
Example 2. Obtainment of different versions of humanised antibody.
The VH and VK IOR C5 sequences were compared with a human sequences
database, obtaining the most human homological sequence with the IOR C5.
Then the amphipatic regions or possible T cell epitopes, were determined in VH and
VK regions.
For VH, mutations were introduced in positions 10 and 17, and the amino acids ASP
and SER by GLY and THR respectively, were substituted. These mutations were
done by PCR overlapping, using primers 1 and 2, 3 and 4 in a first PCR and the
results of these PCR were overlapped in a second PCR, using 2 and 4 primers,
whose sequences are the following: (Kamman, M., Laufs, J., Schell, J., Gronemborg,
B. Rapid insertional mutagenesis of DMA by polymerase chain reaction (PCR).
Nucleic Acids Research 17:5404,1989).
Primers for the mutations 10 and 17 of the heavy chain.
Primer 1: I
5' GAGTCAGGACCTGGCCTGGTGAAACCTTCTCAGACACTTTCACTCACC 3'
Primer 2:
5' TGGGTCGAC(AT)GATGGGG(GC)TGTTGTGCTAGCTGAAGAGAC 3'
Primer 3:
5' GGTGAGTGAAAGTGTCTGAGAAGGTTTCACCAGGCCAGGTCCTGACTC 3'
Primer 4:
5' GGGGATATCCACCATGGCTGTCTTGGGGCTGCTCTTCT 3'
10
After the former mutations were verified by sequencing, new mutations were
introduced to this mutated DNA, the new mutations introduced in positions 43 and 44
were LYS and GLY, substituting ASM and LYS respectively. The overlapping
procedure was done as the previous overlapping. The mutations were verified by
sequencing, this new construction was called CSVHhu.
The primers described for these mutations were:
Primers for the mutations 43 and 44 in the heavy chain.
Primer 1:
5' CAGTTTCCAGGAAAAGGACTGGAATGGATG 3'
Primer 2:
5' TGGGTCGAC(AT)GATGGGG(GC)TGTTGTGCTAGCTGAAGAGAC 3'
Primer 3:
5' CATCCATTCCAGTCCTTTTCCTGGAAACTG 3'
Primer 4:
5' GGGGATATCCACCATGGCTGTCTTGGGGCTGCTCTTCT 3'
For VK the mutations were done in positions 15, 45 y 63 substituting ILE, LYS and
THR, by LEU, ARG y SER, respectively.
The mutations were introduced by overlapping PCR as describe previously. The
sequences of the used primers are shown. The new genetic construction was named
CSVkhu.
Primers for the mutation 15 of the light chain.
Primer 1:
5' TTGTCGGTTACCCTTGGACAACCAGCC 3'
Primer 2:
5' AGCGTCGACTTACGTTT(TG)ATTTCCA(GA)CTT(GT)GTCCC 3'
Primer 3:
5' GGCTGGTTGTCCAAGGGTAACCGACAA 3'
Primer 4:
5' GGGGATATCCACCATGAGG(GT)CCCC(AT)(GA)CTCAG(CT)T(CT)CT(TG)GT
Primers for the mutation 45 of the light chain.
Primer 1:
5' GGCCAGTCTCCAAGGCGCCTAATCTAT 3'
Primer 2:
5' AGCGTCGACTTACGTTT(TG)ATTTCCA(GA)CTT(GT)GTCCC 3'
Primer 3:
5' ATAGATTAGGCGCCTTGGAGACTGGCC 3'
Primer 4:
5' GGGGATATCCACCATGAGG(GT)CCCC(AT)(GA)CTCAG(CT)T(CT)CT(TG)GT
Primers for the mutation 63 of the light chain.
Primer 1:
5' CCTGACAGATTCAGTGGCAGTGGATCA 3'
Primer 2:
5' AGCGTCGACTTACGTTT(TG)ATTTCCA(GA)CTT(GT)GTCCC 3'
Primer 3:
5' TGATCCACTGCCACTGAATCTGTCAGG 3'
Primer 4:
5' GGGGATATCCACCATGAGG(GT)CCCC(AT)(GA)CTCAG(CT)T(CT)CT(TG)GT
All the mutations were verified by sequence.
The humanised VK and VH were cloned into the vectors PAG4622 and PAH4604,
the followings constructions were obtained, C5Vkhu-PAG4622 and CSVHhu-
PAH4604.
The NSO cells were electroporated with 10 ug of the humanised C5VHhu-PAH4604
and 10 ug of the C5VKhu-PAG4622. These vectors were linearized with PVUI
digestion.
The electroporation and detection of the clones expressing humanised antibody IOR
C5h were identical to the previous described for the chimeric antibody.
Example 3. Construction of the single chain Fv fragment:
Construction of the scFv fragment (VH-linker-VL), from variable domains (VH y VL) of
IORC5 mAb. Cloning into expression vector to express in E.Coli.
Procedure (a). Construction of the scFv.-
The strategy has a first round of amplification by PCR, modifying sequenced VH and VL
regions, including restriction endonucleases sites to cloning into the expression vectors
pPACIB.7plus and pPACIB.9plus. In the amplification, the oligonucleotides designed
under the exact sequence are used.
Heavy Chain:
4066; EcoRV-FR1-VH
5'.GGGATATCTGAGGTGCAGCTTCAGGAGTCAGGA..3'
4255: EcoRV-FR4-VR
5'.. CAGGATATCGCAGAGACAGTGACCAGAGTCCC. .3'
Light Chain:
2938: Sal I-FR1-VL
5'.CGICGACGATATCCAGATGAC(AC)CA(GA)ACT(AC)C..3'
2935: Apa I- FR4-VL
5'.ATGGGCCCTTT(TC)A(TG)(TC)TCCAGCTTGGT..3'
After amplifying the regions, were purified and digested VH (EcoRV) and VL (Sall-
Apal). The DMA fragments were purified and ligated with pPACIB.9plus and
pPACIB.7plus, vectors, previously digested with restriction enzymes.
The plasmid pPACIB.7plus is modified to export to periplasm heterologous proteins
whose genes are expressed in E.coli. This plasmid contains regulatory sequences to
get the following functions: Promoter sequence (tryptophan), sequence for signal
peptide (OMPA), sequence for linker peptide (Chaudhary et al., 1990) and a domain
composed by 6 hystidines codified in matures protein's C-terminal to help in the
purification of this protein (Gavilondo, J.V. et al. Proceedings of the IV Annual
Conference on Antibody Engineering. IBC Conferences Inc. Coronado, CA.
December 8-10, 1993).
The plasmid pPACIB.9plus (Figure 1) is modified to express in the cytoplasm
heterologous proteins whose genes are expressed in E.coli. This plasmid contains
regulatory sequences to get the following functions: Promoter sequence (tryptophan),
27aa fragment derived from IL-2h for getting efficient expression of the protein, and a
domain of 6 hystidines codified in matures protein's C-terminal to help in the posterior
purification of this protein (Gavilondo, J.V. et al. Proceedings of the IV Annual
Conference on Antibody Engineering. IBC Conferences Inc. Coronado, CA.
December 8-10, 1993).
The PCR reaction's product was used to transform the competent E.coli cells (strain
MC1061), which were plated under solid selective medium and grown at 37°C. To
select recombinant vectors, a bacterial colonies were inoculated in liquid medium and
extracted plasmid DMA from this culture (Molecular Cloning, A Laboratory Manual,
second edition, 1989, Sambrook, Fritsch and Maniatis). The plasmid DNA was
digested by EcoRV, Sall/Apal, Xhol/Apal according cloning step, after applying under
agarose gel and visualised with UV light, the recombinant clones were select
between the clones with digestion pattern of two bands, one of them corresponding
to pPACIB.7 and 9plus (approx. 2.9kb), and the second to the expected domain
(approx. 320pb VH or VL y 720pb for the scFv). For VH domain the insertion
orientation was checked by DMA sequencing.
Procedure (b). Expression of scFv in E.coli, obtained from variable domain genes of
IOR C5 Mab.
Four strains of E. coli were transformed (TG1, coliB, W3110 y MM294), to study the
cloned gene expression, using two recombinant plasmids selected in (a). Basically
the recombinant bacteria were grown in liquid medium (LB) with ampicillin, overnight
at 37°C. From these cultures, were inoculated fresh cultures containing ampicillin,
and incubated by 3 hrs at 37°C. Then, the expression of the protein was induced,
adding to the culture beta-indolacrylic acid (inductor of the tryptophan promoter). The
analysis of the samples in SDS poliacryilamide gels at 12%, indicated that a protein
of approximately of 28kDa is expressed under these conditions, in the periplasmatic
fraction for the construction of pPACIB.7plus and a 30 kDa band for the recombinant
clone in pPACIB.Splus, which is expressed in TG1 in between 6-11% of the total
bacterial protein. It demonstrated through a Western blot (Molecular Cloning, A
Laboratory Manual, second edition de 1989, by Sambrook, Fritsch and Maniatis) with
an antisera obtained in rabbit against Fab fragment of IOR C5 Mab, and immunopurified,
that this protein corresponds to scFv of IOR C5.
Example 4. Obtention of the scFv from bacterial cultures, renaturalisation and
recognition assays to antigen.
Procedure (a). Extraction and renaturalisation of the scFv of IOR C5 from
recombinant clone in pPACIB.9plus.-
In the extraction process of the protein from the producer cells using rupture
ultrasound process, that allowed to separate soluble and insoluble fractions,
combining with SDS-polyacrilamide electrophoresis gels, transferred to nitro-cellulose
and Western blot, evidenced that the protein remains in the insoluble bacterial
fraction.
Under these circumstances the protein was partially purified in a process including
the followings steps:
(1) separation of the soluble and insoluble material by ultrasound and centrifugation,
(2) wash in low molarities of urea (2 M) and
(3) solubilization to high molarities of Urea (6 M).
From the solubilized material, the protein is purified in affinity chromatography to
metallic ions and renaturalised against buffer solution.
Procedure (b). Binding assay to tumour cells of the scFv-IORC5 fragment.
Cell lines:
The cells were obtained from Centra de Inmunologia Molecular. SW948
adenocarcinome cell line was grown in L-15 medium supplemented with 10% bovine
foetal serum at 37°C in 6 % COa. Raji cell line (Burkitt human limphome) and Hut 78
(T human cell line) were used as negative controls.
These cell lines were grown in RPMI1629 supplemented with 10% bovine foetal
serum at 37°C.
The cell suspensions were fixed to 106 cell/ml in PBS containing 1% albumin of
bovine serum. 10 ul of cell suspension was added to each well. The slides were dried
in the dusty free air during 3 hours and fixed in acetone-methanol (1:1) solution, 5
minutes, and hydrated in TBS by 10 minutes. Finally, the cells were processed, using
immunocytochemistry assay.
The activity of scFv IORC5 fragment was determined using immunocytochemistry
assay, trough immunoperoxidase technique. The cells were incubated during 2 hours
at 37°C with single chain Fv IOR C5, followed by incubation with anti Fab serum and
with an anti-mouse peroxidase conjugated (HRPO), each one for 30 minutes at room
temperature. The localisation site of the peroxidase were visualised with solution
which contains 5 mg of 3-3 diaminobencidine, 5 -ml of TBS and 5 pi of H202, 30 %.
Between incubations, the slides were washed with cold TBS.
After introducing in water, the slides were contrasted with Hematoxilline of Mayer and
Canadian Balsam was added. Each experiment included positive and negative
controls.
The immunocytochemistry studies revealed that this fragment is only positive to
SW948 cell line, that showed a moderate labelled comparing with the complete Mab,
demonstrated a specific recognition of the scFv IORc5 to this cell line. The label was
associated to the membrane and cytoplasm compartment in the malignant colon
cells.
Brief description of the Figures.
Figure 1: Shows the genetic construction of the plasmid pPACIB.9plus, which
is a modified plasmid to express fusion proteins in the cytoplasm of E.coli. This
plasmid contains regulatory sequences to get the following functions: Promoter
sequence (tryptophan), 27aa fragment derived from IL-2h for getting efficient
expression of the protein and, a domain of 6 histidines codified in mature protein's Cterminal
to be used during the purification of this protein.





WE CLAIM:
1. A recombinant antibody or a single chain Fv fragment derived from murine monoclonal antibody IOR C5 or a mutant thereof expressed by hybridoma deposited as ECCC 97061101, wherein the antibody or Fv Fragment comprises CDR regions and framework regions in light and heavy chains.
2. A recombinant antibody as claimed in claim 1, wherein the light and heavy chain comprises complementary determining region derived from IOR C5 antibody and human constant region.
3. A recombinant antibody or a single chain Fv fragment as claimed in claim 1 , wherein the CDR Sequence of heavy chain is selected from:
CDR1: SDYNWH
CDR2: YISYNGTTSYNPSLKS
CDR3: NDEKAWFAY
4. A recombinant antibody or a single chain Fv fragment as claimed in claim 1, wherein
the CDR Sequence of light chain is selected from:
CDR1: KSSQSLLDSDGKTYLN CDR2: LVSKLDS CDR3: WQGTHFPHT
5. A recombinant antibody as claimed in claim 1, wherein the antibody is a chimeric
antibody and wherein the CDRs and framework (FR) regions of the antibody are
derived from murine monoclonal antibody IOR C5 and human constant regions of
light and heavy chain.
6. A recombinant antibody or a single chain Fv fragment as claimed in claim 1, wherein
the framework sequence for heavy chain is selected from:
FR1: DVQLQESGPGLVKPSQTLSLTCTVTGYSIT FR2: WIRQFPGKSGLEWMG
FR3: RISITRDTSKNQFFLQLNSVTTEDTATYYCAR FR4: WGQGTLVTVSA

7. A recombinant antibody or a single chain Fv fragment as claimed in claim 1, wherein
the framework sequence for light chain is selected from:
FR1: DVVMTQTPLTLSVTLGQPASISC
FR2: WLLQRPGQSPRRLIY
FR3: GVPDRFSGSGSGTDFALKIRRVEAEDLGVYYC
FR4: FGGGTKLEIKRKSTLTG
8. A recombinant antibody as claimed in claim 1, wherein the antibody is a humanized antibody with a point mutation in the framework region of light and heavy chain.
9. A recombinant antibody as claimed in claim 8, wherein sites of point mutation in heavy chain are:
Position 10 ASP by GLY Position 17 SERb y THR Position 43 ASN by LYS Position 44 LYS by GLY
10. A recombinant antibody as claimed in claim 8, wherein sites of point mutation in light
chain are:
Position 15 ILE by LEU Position 45 LYS by ARG Position 63 THR by SER
11. A host cell such as E. coli capable of expressing the single chain Fv fragment as claimed in any of the claims 1 and 3, 4, 6 and 7.
12. A recombinant antibody, a single chain Fv fragment and a host cell substantially such as herein described with reference to the accompanying drawings and as illustrated in the foregoing examples.

Documents:

IN-PCT-2001-00631-DEL-Abstract-(30-07-2008).pdf

in-pct-2001-00631-del-abstract.pdf

IN-PCT-2001-00631-DEL-Claims-(30-07-2008).pdf

in-pct-2001-00631-del-claims.pdf

in-pct-2001-00631-del-correspondece-others.pdf

IN-PCT-2001-00631-DEL-Correspondence-Others-(13-08-2008).pdf

IN-PCT-2001-00631-DEL-Correspondence-Others-(30-07-2008).pdf

in-pct-2001-00631-del-description (complete)-22-08-2008.pdf

in-pct-2001-00631-del-description (complete)-30-07-2008.pdf

in-pct-2001-00631-del-description (complete).pdf

IN-PCT-2001-00631-DEL-Drawings-(30-07-2008).pdf

in-pct-2001-00631-del-drawings.pdf

IN-PCT-2001-00631-DEL-Form-1-(30-07-2008).pdf

in-pct-2001-00631-del-form-1.pdf

in-pct-2001-00631-del-form-13-(30-07-2008).pdf

in-pct-2001-00631-del-form-18.pdf

IN-PCT-2001-00631-DEL-Form-2-(30-07-2008).pdf

in-pct-2001-00631-del-form-2.pdf

IN-PCT-2001-00631-DEL-Form-26-(30-07-2008).pdf

IN-PCT-2001-00631-DEL-Form-3-(30-07-2008).pdf

in-pct-2001-00631-del-form-3.pdf

in-pct-2001-00631-del-form-5.pdf

in-pct-2001-00631-del-pct-210.pdf

IN-PCT-2001-00631-DEL-PCT-304-(13-08-2008).pdf

IN-PCT-2001-00631-DEL-Petition-137-(30-07-2008).pdf

IN-PCT-2001-631-DEL-Abstract-(22-08-2008).pdf

IN-PCT-2001-631-DEL-Claims-(22-08-2008).pdf

IN-PCT-2001-631-DEL-Correspondence-Others-(22-08-2008).pdf

IN-PCT-2001-631-DEL-Form-1-(22-08-2008).pdf

IN-PCT-2001-631-DEL-Form-2-(22-08-2008).pdf


Patent Number 222990
Indian Patent Application Number IN/PCT/2001/00631/DEL
PG Journal Number 37/2008
Publication Date 12-Sep-2008
Grant Date 29-Aug-2008
Date of Filing 13-Jul-2001
Name of Patentee CENTRO DE INMUNOLOGIA MOLECULAR
Applicant Address CALLE 216 Y 15, ATABEY, PLAYA, C.HABANA 12100, CUBA.
Inventors:
# Inventor's Name Inventor's Address
1 MATEO DE ACOSTA DEL RIO CRISTINA MARIA OF CALLE C NO. 9510 ENTRE 6 Y 10,ALTAHABANA, CIUDAD HABANA, CUBA.
2 ROQUE NAVARRO CALLE 13 NO. 4211 ENTRE 42 Y 44, PLAYA, CIUDED DE LA HABANA, CUBA.
3 MORALES MORALES ALEJO OF SANTA FELICIA NO. 426 ENTRE MELONES Y R. ENRIQUE, 10 DE OCTUBRE, CIUDAD DE LA HABANA, CUBA.
4 AYALA AVILA MARTA OF CALLE 186 NO. 3117 ENTRE 31 Y 33, PLAYA, CIUDAD DE LA HABANA, CUBA.
5 DUENAS PORTO MARTA OF CALLE 186 NO. 3117 ENTRE 31 Y 33, PLAYA, CIUDAD DE LA HABANA, CUBA.
6 RENGIFO CALZADO ENRIQUE OF CALLE 170 NO. BCE2 APTO. 16, PLAYA, CIUDAD DE LA HABANA, CUBA.
7 PEREZ RODRIGUEZ ROLANDO OF JUAN DELGADO NO. 567 ENTRE ACOSTA Y O'FARRELL, 10 DE OCTUBRE, CIUDDAD DE LA HABANA, CUBA.
8 GAVILONDO COWLEY JORGE VICTOR OF CALLE G NO. 460, APTO.11, PLAZA DE LA REVOLUCION, CIUDAD DE LA HABANA, CUBA.
9 BELL GARCIA HANSSEL OF CALLE 62 NO. 906 APTO. 16 ENTRE 9 Y 11, PLAYA, CIUDAD DE LA HABANA,CUBA.
10 IZNAGA ESCOBAR NORMANDO OF AVE. 31 NO. 32005 ENTRE 320 Y 322, RPTO. FRAGA, LA LISA, CIUDAD DE LA HABANA, CUBA.
11 RAMOS ZUZARTE MAYRA OF CALLE 184 NO. BELL1, APTO.12, ENTRE 1RA Y 5TA, PLAYA, CIUDAD DE LA HABANA, CUBA.
PCT International Classification Number C07K 16/00
PCT International Application Number PCT/CU2000/000004
PCT International Filing date 2000-11-16
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 CU 196/99 1999-11-16 Cuba