Anti-DNP antibody responses to DNP-histone H1 in mice

Anti-DNP antibody responses to DNP-histone H1 in C3H/HeN mice were not suppressed by in vivo treatment with carrageenan in which many phagocytic macrophages were presumed to be impaired. Rather higher antibody responses to this antigen were observed in athymic nude mice than in heterozygous nude mice. Further, non-adherent spleen-cell and T-cell depleted spleen cells induced in vitro anti-DNP antibody responses to DNP-histone H1 to the same extent as normal spleen cells. These results suggest that anti-DNP antibody responses to DNP-histone H1 are macrophage- and thymus-independent. It was also observed that IgG-type anti-DNP antibodies to DNP-histone H1 were produced although most thymus-independent antigens were shown to induce predominantly IgM type antibodies but little, if any, IgG type antibodies. Furthermore, histone H1 did not show any polyclonal B-cell activator activities in contrast to many other thymus-independent antigens which act as polyclonal B-cell activators.