Rabbit autoantibodies to actin induced by immunization with heterologous actins; a possible mechanism of smooth muscle antibody production.

Antisera against actins from chicken gizzard smooth muscle and ascaris body wall were prepared in rabbits. Immunological cross-reactivity of the antisera with actins of several different species was demonstrated by precipitation reactions in agarose gels and by immunofluorescence studies. The antisera were also reactive with actin of rabbits, the homologous animal used for immunization. The latter finding indicated termination of natural tolerance to actin by immunization of cross-reactive actins. A possible mechanism operating in the induction of smooth muscle antibodies, autoantibodies which have a similar nature to the anti-actin antibody is discussed in relation to the termination of natural tolerance to actin.