An idiotope expressed on a monoclonal antibody specific for human haemoglobin beta chain and naturally occurring immunoglobulin(s).

Abstract

HId-1A (gamma 1:kappa), HId-2a (mu:kappa) and HId-4a (gamma 1:kappa) monoclonal anti-idiotopes of BALB/c origin were induced by the human haemoglobin-reactive, B10.D2-derived monoclonal antibody Hb-2d. HId-1a and HId-4a seem to react with the same idiotope and may, in fact, be encoded by the same V, D and J genes. HId-2a, on the other hand, seems to react with an idiotope different from that recognized by the other two anti-Id's and present in the sera of non-immune B10-H-2 congenic mice. HId-2a, but not HId-1a or HId-4a, may react with an idiotope in or near the antigen binding site of Hb-2d. Naturally occurring immunoglobulin carrying the HId-2a idiotope was affinity-purified from the pooled sera of B10-H-2 congenic mice and partially characterized. It possesses primarily the gamma 2b heavy chain, but small amounts of gamma 1, gamma 2a and mu heavy chains are also detectable. The kappa and lambda 1 light chains are both present in significant amounts. In addition, the affinity-purified immunoglobulin is unreactive with human haemoglobin, is not a rheumatoid factor and does not express in detectable amounts the idiotope recognized by HId-1a and HId-4a. It is possible that all or some part of this polyclonal reagent is specific for antigens normally present in the environment.