Anti-phosphorylcholine (PC) memory was elicited when spleen cells of primed BALB/c mice were challenged in vitro with PC-KLH, IgA, IgG, and IgM PFC were expressed in approximately equal proportions. Optimal responses for all immunoglobulin classes occurred when cultures received 10-3 to 10-1 μg/ml PC-KLH and were assayed on days 7 to 9. The anti-PC IgG response was expressed in all 4 subclasses although to the greatest extent in IgG1. Memory precursors for all 3 classes persisted in the spleen for at least 13 mo after priming. Analysis of PFC avidity by hapten inhibition and expression of the T15 idiotype by inhibition with a rabbit anti-T15 serum indicated that the 3 immunoglobulin classes differed in heterogeneity. IgM PFC were relatively homogeneous in avidity for PC, and the IgM hapten inhibition profile resembled that of TEPC 15. The IgA response also included PFC that were similar in avidity to TEPC 15, but in addition expressed a population of higher avidity PFC (inhibited by 10-6 M PC), which was undetected in the IgM response. Both IgM and IgA anti-PC PFC were dominated by the T15 idiotype whether antigen challenge occurred in vitro or in vivo. In contrast the avidity of IgG anti-PC PFC differed greatly from TEPC 15, consisting of PFC that were higher in avidity (inhibited by ≤ 10-6 M PC) and PFC that were lower in avidity (inhibited by > 10-3 M PC). Furthermore, neither in vitro nor in vivo generated IgG PFC were dominated by the T15 idiotype although expression of T15+ IgG PFC was greater in vivo than in vitro. This asymmetry in idiotype dominance may be due to a greater proportion of T15- clones among IgG precursors as compared to IgM and IgA, with the expression of these precursors being favored in vitro. These results suggest that 1) there may be a less rigorous maintenance of idiotype dominance among IgG memory precursors as compared to IgM and IgA memory precursors, or 2) idiotype by T15 memory precursors of the 3 isotypes may be affected by separate mechanisms.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Immunology|
|State||Published - Jan 1 1981|
ASJC Scopus subject areas
- Immunology and Allergy