title: Cellular events in tolerance IX: maintenance of immunological tolerance in the presence of normal b-cell precursors and in the absence of demonstrable suppression.
abstract: The cellular events involved in immunological tolerance to fluoresceinated sheep gammaglobulin (FL-SGG) were analyzed at the level of hapten-specific B cells. One single iv injection of FL-SGG induced tolerance as measured by challenge with thymus-dependent (FL-KLH) or thymus-independent (FL-Ficoll) antigens in vivo or thymus-independent (FL-LPS) antigen in vitro. As noted earlier, unresponsiveness was maintained until 6-8 weeks after tolerance induction. Limiting-dilution precursor analysis demonstrated a reduction in B-cell precursors on Day 7 after tolerogen treatment; precursor frequencies returned to control levels by 3-4 weeks. This recovery of precursors in the presence of stable tolerance was not due to suppressor activity. Rather, results show that tolerant hapten-specific B cells are clonally anergic and display a reduced burst size in response to antigen. Hence, unresponsiveness is maintained in the presence of apparently normal precursor levels by an intrinsic defect in antigen-specific B cells.
mesh_terms: D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D005452:Fluoresceins; D007108:Immune Tolerance / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D051381:Rats; D011917:Rats, Inbred Lew; D012756:Sheep / Q000276:immunology; D005719:gamma-Globulins / Q000494:pharmacology
chemical_list: D005452:Fluoresceins; D005719:gamma-Globulins