Selective impairment of B cell function by Neisseria meningitidis.
Spleen cells from CBA/J mice infected with Neisseria meningitidis displayed depressed in vitro plaque-forming cell (PFC) responses to T-dependent (sheep red blood cell; SRBC) and T-independent (TNP-LPS, TNP-Ficoll) antigens. The inhibition was observed over a wide range of antigen concentrations. The decreased responsiveness of splenocytes from infected mice was due to a selective impairment of B-cell function since helper-T-cell activity was intact in infected mice as shown by the ability of T-enriched lymphocytes to cooperate with normal B-enriched lymphocytes in the generation of an anti-SRBC response, accessory macrophage function was preserved since adherent spleen cells from bacteria-injected mice were shown to produce normal or increased levels of IL-1 and were able to cooperate with normal non-adherent spleen cells in the generation of PFC against SRBC. Addition of peritoneal cells from normal animals or extraneous IL-1 both failed to restore normal PFC responses in cultures of splenocytes from infected mice. Finally, B-enriched lymphocytes from infected mice produced poor anti-SRBC responses when cultured with either Con A supernatant or T-enriched lymphocytes from normal or infected mice. Cell-mixing experiments failed to detect the presence of suppressor cells in cultures of unfractionated spleen cells or B-enriched lymphocytes from infected mice. Therefore, the immunological unresponsiveness associated with a Neisseria meningitidis infection was attributed to a meningococcus-induced defect(s) in B-cell function. In vivo polyclonal B-cell activation leading to clonal exhaustion did not play a major role in the depression of humoral responses since meningococcal infection induced little or no polyclonal Ig secretion.
D000818:Animals; D000917:Antibody Formation; D000938:Antigen-Presenting Cells / Q000276:immunology; D000955:Antigens, T-Independent / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D007108:Immune Tolerance; D008264:Macrophages / Q000276:immunology; D008297:Male; D008585:Meningitis, Meningococcal / Q000276:immunology*; D051379:Mice; D008808:Mice, Inbred CBA; D009345:Neisseria meningitidis / Q000276:immunology; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
D000955:Antigens, T-Independent