Figure 6.

Neonatal or adult treatment with SpA causes a persistent tolerance to PC-containing immunogens. Postimmune responses were measured 10 d after challenge of 3-mo-old mice (A) with pronase-treated extract of R36A pneumococcal bacteria and B1355 dextran in CFA, and (B) with PC-KLH emulsified in CFA. (C) Adult BALB/c mice were treated with SpA, and then challenged 7 d later. Detection of anti-PC responses used the T15 clone–specific AB1-2 antibody, which recognizes an idiotope requiring coexpression of both the T15 V_H and V_L regions (reference 21), and also the clan III–restricted avian mAb, LJ-26 (reference 12). Groups are indicated by the protein with which they were conditioned and subsequently challenged, with comparison to control groups of naive mice challenged with R36A and dextran in CFA (Naive/R36A Dex), and to naive mice that received CFA alone (Naive/CFA). Values are relative antibody units per milliliter. *P < 0.05; **P < 0.01; ***P < 0.005; ****P < 0.001.