Fine specificity and idiotypes of early antibodies against (4-hydroxy-3-nitrophenyl)acetyl (NP)

Earlier studies have demonstrated that antibodies of the primary response (days 14 to 30) to (4-hydroxy-3-nitrophenyl)acetyl (NP) of C57BL, LP, and 101 mice share idiotype NPb and are heteroclitic (the affinity for certain chemical analogues of NP is higher than the affinity for NP), whereas BALB/c antibodies share idiotype NPa and are homoclitic. Both idiotypes are inherited as allotype-linked traits and have the lambda-chain as the predominant light chain. This study was extended to earlier anti-NP antibodies (7 days) of eight mouse strains (42 individuals) and to anti-NP hybridoma proteins originating from day 6 spleen cells. Only one of the early 42 antisera was found to be homoclitic, and no genetic polymorphism was detectable in fine specificity. In contrast, idiotypes NPa and NPb still followed the genetic rules that had been established earlier. lambda-Chain-bearing BALB/c hybridoma proteins from day 6 of the primary response were more heteroclitic than kappa-chain bearing ones (Krel greater than 20), but two out of three kappa proteins were also heteroclitic (Krel approximately 2). Our results caution against the use of the heteroclitic fine specificity as a typing method. In contrast, they reinforce the value of anti-idiotypic antibodies for this purpose.