The Immune Response to Pneumococcal Polysaccharide Type III is Followed by Increased Production of an Antibody Antifactor

Abstract

The study shows that serum from pneumococcal polysaccharide type III (SSSIII)-immunized and nonimmunized mice that has been absorbed until devoid of anti-SSSIII antibodies inhibits anti-SSSIII plaque-forming cells (PFC) but not antisheep red blood PFC in antibody plaque assay. A large fraction of the inhibitions activity can be absorbed by and eluted from anti-SSSIII-Sepharose, but not normal mouse serum-Sepharose. It has low or no affinity for protein A and concanavalin A. The titre of the inhibitor increases with repeated immunizations and inhibits the anti-SSSIII PFC of rats or mice of different allotypes. On the basis of these characteristics, I classify the inhibitor as an anti-idiotypic nonimmunoglobulin factor directed against a common determinant of anti-SSSIII antibodies of mouse and rat, with an immuno-regulatory function.

Purification of an IgM Antibody Response‐Enhancing Factor to the Alpha 1–6 Epitope of Native Dextran from Serum and Supernatants from T‐Cell Hybridomas

“…From previous research carried out in our laboratory, we had reason lo believe that in addition to anti-idiotypic antibodies |5.6] Tcellderived, antigen-spetific products are also secreted in the serum duritig the immune responses to some T-independent antigens, such as native dextran and Type III pneumococcal polysaccharide. Such factors can be demonstrated by their ability to specifically inhibit in vitro plaque-forming cells (PFC) (16]. To study these factors further, we produced T-cell hybrids by hybridizing spleen cells from dextranimmunized mice witb AKR thymoma BW5147 and selected the positive clones capable of inhibiting the anti-Dx PFC.…”