Blocking of primary in vitro antibody responses to thymus-independent and thymus-dependent antigens with antiserum specific for IgM or IgD

The effect of anti-μ and anti-δ on the primary in vitro IgM response of murine splenocytes to thymus-dependent (trinitrophenylated erythrocytes) and thymus-independent (trinitrophenylated brucella) forms of trinitrophenyl was studied. The results indicate that either anti-μ or anti-δ can block the response of adult splenocytes to the thymus-dependent antigen. The thymus-dependent responses of neonatal splenocytes that bear a low concentration of IgD were also abrogated by treatment with anti-δ. In contrast, anti-μ, but not anti-δ, blocked the response of adult plenocytes to the thymus-independent antigen used. These results indicate that both IgM and IgD are receptors required for triggering cells by a thymus-dependent antigen but that only IgM receptors are required for triggering by the thymus-independent antigen used.