Cross-reactive idiotypes on rabbit anti-SEA antibodies stimulate anti-idiotype spleen and lymph node cell responses of mice infected with Schistosoma mansoni

Abstract

Antibodies to Schistosoma mansoni soluble egg antigens (SEA) generated in outbred rabbits from two different sources were used to study cross-reactive idiotype/anti-idiotype (Id/anti-Id) interactions in S. mansoni-infected mice in two different locations. Immunoaffinity purified rabbit polyclonal anti-SEA antibody preparations (RabId) were predominantly Ig by SDS-PAGE and demonstrated anti-SEA activity by ELISA and Western blot. RabId prepared from three separate rabbits and used at 40 micrograms/ml in vitro stimulated lymphocyte proliferative responses of spleen cells from mice with eight week infections (Mean +/- SEM [E-C]) of 3869 +/- 764, 18594 +/- 3046 and 8962 +/- 1734 cpm. Spleen cells from uninfected mice exposed to the same RabId preparations in vitro had respective [E-C] values of 206 +/- 144, 494 +/- 154 and 363 +/- 180. Lymph node cells from mice infected for 8 weeks demonstrated [E-C] of 123 +/- 400, 5073 +/- 828 and 2361 +/- 656 upon exposure to these 3 RabId preparations. Lymph node cells from uninfected mice had [E-C] of 220 +/- 76, 194 +/- 82 and 143 +/- 72 when exposed to these RabId. Maximum in vitro proliferative response to Ig from unimmunized rabbits was 761 +/- 400 by spleen cells from mice with eight week infections. These data indicate the presence of cross-reactive Id on rabbit anti-SEA antibodies from different rabbits that can stimulate in vitro lymphoproliferative responses of spleen or lymph node cells from S. mansoni-infected mice.