Analysis of the primary anti-(4-hydroxy-3-nitrophenyl) acetyl (NP) responsive B cells in BALB/C and B10.D2 mice

The chain composition and fine specificity of the anti-(4-hydroxy-3-nitrophenyl) acetyl (NP) response was examined at the level of individual clones in BALB/c (Ig-1a allotype) and B10.D2 (Ig-1b) mice. The primary anti-NP serum response of B10.D2 is distinguished from that of BALB/c by its restricted heterogeneity and unusual heteroclitic fine specificity, which appear to be associated with antibodies bearing a unique allotype-linked idiotype(s) (NP-b) paired with lambda light (L) chains. At the clonal precursor level, the 10.d2 anti-NP primary response was found to be characterized by less diversity than that of BALB/c and is dominated by several clonotypes with the heteroclitic fine specificity. However, BALB/c also possess abundant heteroclitic precursors (53%), which are expressed but apparently obscured in its more heterogeneous serum response. Heteroclitic fine specificity in both strains is occasionally associated with clones bearing kappa as well as lambda L chains.