Normal tolerance characteristics of the antibody-forming cell precursors of the NZB mouse.

Splenic PFC dose-response curves were measured in normal mice and in mice of the autoimmune NZB strain for the thymus-independent antigens pneumococcal polysaccharide type 3 (SIII) and bacterial levan. There were differences between the strains in the maximal response achieved to each antigen, but the level at which high dose tolerance occurred was the same in all the strains. The splenic anti-sheep erythrocyte plaque-forming cell dose-response curve of lethally-irradiated, bone marrow restored NZB mice was compared with that of (C57/B1 × BALB/c)F hybrid and (NZB × BALB/c)F hybrid mice. Although the dose-response curves of the two hybrid stains were less sharp than that of the NZB, the peak response occurred at the same dose of SRBC (10, i.v.), and reached the same level, tailing off at higher doses. These results indicate that the B cells of NZB mice display normal high-dose tolerance characteristics, at least to these three antigens.