Immunofluorescence Studies on Thymocytotoxic Antibody from New Zealand Black Mice

Abstract

Abstract Natural thymocytotoxic antibody (NTA) which occurs in high titer in New Zealand Black (NZB) mice was compared with AKR anti-θ (C3H) antiserum for ability to induce redistribution of C57BL/6 thymocyte surface antigen. NTA reacted with both thymocytes and brain cells bearing either the θ-AKR or θ-C3H alloantigens and was found to be an IgM antibody. Anti-θ (C3H) was purified to obtain the IgG fraction which was used in these studies. Neither NTA nor anti-θ antibody induced cap formation alone, however, both formed caps upon the addition of specific anti-immunoglobulin sera. Studies involving the sequential exposure of thymocytes to both antibodies demonstrated that θ and NTA reactive antigen co-migrate on the thymocyte surface. These studies suggest that NTA reacts with a determinant common to both the θ-AKR and θ-C3H alloantigens.