Tissue Distribution of the Erythrocyte-2.1 (Ea-2.1) Antigen

Abstract

Various murine tissues were tested for the presence of the erythrocyte-2.1 antigen. The antigen is known to be present on erythrocytes of B10. RIII(R) mice. A more complete description of tissue distribution was desired. By using absorption and cytotoxic assays it was determined that the erythrocyte-2.1 (Ea-2.1) antigen is located on splenocytes of B10. RIII(R) mice. The antigen is also located on the T and B lymphocytes of this strain. Liver and brain cells from B10. RIII(R) mice tested negatively for the presence of the antigen. Along with studies on tissue distribution of the Ea-2.1 antigen, the cross reactivity of a monoclonal antibody that is specific for Ea-2.1 was investigated. The monoclonal antibody used in these tests was MA 204. The antibody was found to cross react with lymphocyes from B10. SM mice. These mice do not carry the Ea-2.1 antigen. B10 and B10. SM mice are congenic except for their H-2 haplotype. B10 mice will not immunologically respond to the Ea-2.1 antigen. B10. SM has an H-2V haplotype with which the antibody will cross react. A recombinant of B10.SM, B10. SM (22R), was tested against MA 204. B10. SM (22R) has an H-2azl haplotype. This strain did not cross react with the antibody. From this it was inferred that the monoclonal antibody specific for the Ea-2.1 antigen was cross reacting with an antigen encoded by neither the D nor £ subregion of the LL2V gene complex.