A newly characterized group of anti-phosphocholine antibodies: group III antibodies

Four anti-phosphocholine (PC) monoclonal antibodies (MAbs) are described that can be clearly distinguished from group I and II anti-PC antibodies [Chang et al. (1982) J. Immun. 128, 702-706]. They bind optimally and suboptimally PC-histone coated ELISA plates equally well, in contrast to group I and II MAbs which bind much less well to suboptimally coated plates. On optimally coated plates their fine specificity for PC analogues is group II-like, whereas on suboptimally coated plates it is group I-like; group I and II MAbs each maintain their own characteristic fine specificity patterns on either type of plate. At the molecular level, all four MAbs utilize VK24 light chains and share a 5.2 kb rearranged band in Southern blot analysis (using a JH probe and EcoRI restricted DNA). The term “group III” is proposed to define and distinguish these anti-PC antibodies.