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The MoAb‐VκIIIb Cross‐Reactive Idiotope on A27a (Humkv325) Encoded Kappa Chains Maps to Framework Region 3
Author(s) -
POTTER K. N.,
LI Y. C.,
ABRAHAM G. N.,
CAPRA J. D.
Publication year - 1996
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1046/j.1365-3083.1996.d01-319.x
Subject(s) - kappa , immunoglobulin light chain , chain (unit) , antibody , idiotopes , microbiology and biotechnology , chemistry , stereochemistry , monoclonal antibody , medicine , biology , monoclonal , immunology , physics , mathematics , geometry , astronomy
The monoclonal antibody MoAb‐VκIIIb binds a cross‐reactive idiotopic (CRI) determinant on light (L) chains encoded by the VκIIIb subgroup A27a (Humkv325) gene segment. The aim of this study was to localize the MoAb‐VκIIIb CRI. Mutational analyses involving region exchanges between a CRI‐positive VκIIIb chain and a CRI‐negative Vκ1 chain indicate that the MoAb‐VκIIIb CRI is located in framework region (FR) 3 of A27a (Humkv325) encoded L chains. CRI‐positive kappa chains unpaired with a heavy (H) chain are reactive with MoAb‐VκIIIb, indicating that the CRI is located on the kappa chain alone without involvement of H chain residues. Combinatorial antibodies composed of non‐parental L and H chain pairings are reactive with MoAb‐VκIIIb only when the L chain is A27a (Humkv325) encoded. The CRI, therefore, is not readily perturbed by H chain interactions. When the FR3 from a CRI‐positive kappa chain replaced the FR3 in a CRI‐negative lambda chain, the determinant was no longer detectable with MoAb‐VκIIIb. It is possible, therefore, to exchange regions between kappa chains from different families and retain the CRI structure, however the determinant is lost when placed in a more foreign background such as a lambda chain. These data more precisely define the interaction between MoAb‐VκIIIb and its CRI, and indicate that there are limits within which antibody FRs can be shuffled and still retain their native structural features.