Studies on antigenic variation of cyclically transmitted Trypanosoma congolense.

Antigenic variants of T. congolense transmitted by G. m. morsitans through normal and X-irradiated mice were investigated by means of the neutralization test and IFAT. Clones of a cyclically passaged derivative strain were isolated from irradiated and normal mice. The IFAT revealed cross immunofluorescent reactions between most of the stabilates, whereas only the two clones obtained from irradiated mice were totally neutralized by their homologous antisera. These two antisera showed no cross neutralizing activity. The results indicate a possible antigenic heterogeneity of the extruded metacyclic forms.