Occurrence of a theta-like antigen in rats

A rat antigen system parallel to the mouse theta system has been described(*) All rat strains tested expressed an antigen cross-reactive with the theta-AKR specificity of mice while none cross-reacted strongly with theta-C3H. The rat antigen may be demonstrated by either absorption or direct complement-mediated killing of rat thymocytes. Patterns of organ distribution and developmental appearance in the nervous system of rats also parallel those previously reported for theta in mice.