Identification of H‐2 and Ia‐Antigen Analogues in Several Species by Immunological Crossreactions of Xenoantisera

Rabbit antisera against H-2K and D antigens react with molecules composed of 12,000 and 45,000 dalton subunits derived from human, monkey, rat, guinea-pig, cow and pig lymphocytes. The antisera failed, however, to react with similar type molecules from chicken. A rabbit antihuman beta 2-microglobulin serum reacted with chicken molecules comprising 12,000 and 45,000 dalton polypeptide chains. An antiserum against HLA-DR antigens reacted with Ia-antigen-like molecules from monkey, rat, mouse, guinea-pig, cow, pig and chicken lymphocytes. All Ia-antigen-like molecules displayed two dissimilar subunits. The present data suggest that xenoantisera directed against highly purified MHC antigens from one species may be useful tools in elucidating the structure of similar antigens in other species where alloantisera are not available.