Mechanisms of specific immunological unresponsiveness to bacterial lipopolysaccharides.
Low-dose priming of mice with Escherichia coli O113 lipopolysaccharide (LPS) results in the development of immunological memory, whereas low-dose priming with E. coli O55 LPS or Serratia marcescens LPS induces significant antigen-specific unresponsiveness. All three preparations of LPS induced proliferation of mouse splenocytes with similar time course and [3H]thymidine uptake. There was no correlation between the small amounts of serum antibody detected by enzyme-linked immunosorbent assay after low-dose priming and the subsequent generation of either memory or unresponsiveness. Further, the passive transfer of small amounts of LPS-specific antibody had no significant effect on the magnitude of the plaque-forming cell (PFC) response elicited after subsequent immunization. Reduction of the PFC response to E. coli O55 LPS occurred after low-dose priming of nu/nu (as well as nu/+) mice; however, unresponsiveness could not be generated in nu/nu mice by low-dose priming with S. marcescens LPS. Thus, although the development of low-dose unresponsiveness to S. marcescens LPS appears to involve T cells, the response of E. coli O55 LPS does not. Enhancement of the primary PFC response to S. marcescens LPS could be transferred with low-dose primed spleen cells depleted of Lyt-2+ T cells; this suggests that the magnitude of the PFC response to this preparation of LPS is negatively influenced by Lyt-2+ T cells and positively influenced by Lyt-2- spleen cells (i.e., L3T4+ T cells). These findings indicate that T cells appear to be involved in regulating the magnitude of the antibody response to some types of bacterial LPS.
Elkins
K L
KL
Laboratory of Microbial Immunity, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
Stashak
P W
PW
Baker
P J
PJ
D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D000950:Antigens, Ly / Q000032:analysis; D004306:Dose-Response Relationship, Immunologic; D004926:Escherichia coli / Q000276:immunology*; D005260:Female; D007108:Immune Tolerance; D007116:Immunization, Passive; D007156:Immunologic Memory; D008070:Lipopolysaccharides / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008819:Mice, Nude / Q000276:immunology; D012706:Serratia marcescens / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D000950:Antigens, Ly; D008070:Lipopolysaccharides