SPECIFIC AND NONSPECIFIC T-CELL ACTIVATION IN HIGH AND LOW ANTIBODY-PRODUCING MICE (SELECTION IV-A)

The T-cell regulatory function has been evaluated in lines of mice gen etically selected according to the High (H) and Low (L) antibody respo nsiveness to heterologous erythrocytes. The inhibition of antibody pro duction following CD4(+) subset depletion was stronger in L than in H mice. The dose of CD4-specific monoclonal antibody (MoAb) needed for a 50% inhibition of the anti-sheep erythrocyte antibody response was mu ch lower in L mice, even when their responsiveness was improved by rep eated antigen injections or by co-injection of lipopolysaccharide as a n adjuvant. Lymph-node cells from L mice responded normally or even be tter than those from H mice to in vitro non-specific triggering via le ctins, exogenous superantigens or CD3-specific MoAb. In contrast, the antigen-specific responses of the lymph-node cells from protein-primed mice were consistently lower in the Low responder mice. Altogether th e results suggest that a defective stimulation of T helper lymphocytes by the antigen contributes to the weak antibody response of L mice.