An egg surface antigen of Setaria digitata (filariae) shed on development to microfilariae.

Egg surface antigens of Setaria digitata were investigated by an immunoperoxidase staining technique. Certain antigens on the egg surface were shed when the eggs developed to microfilariae. Rabbit antisera to S. digitata eggs and to the soluble egg antigen reacted (as detected by immunoperoxidase staining) with the surface antigens of S. digitata eggs and immature microfilariae, and with mature microfilariae of Wuchereria bancrofti and Dirofilaria repens, but not with the surface antigens of mature microfilariae of S. digitata.