Proteins of Nippostrongylus brasiliensis analyzed by immunoblotting.

Antigenic proteins were characterized by the immunoblotting technique with sera from rats and mice after infection as well as hyperimmune sera. The immune response of infected animals was mainly directed toward five proteins of adult worms (190, 118, 110, 98, and 52 kDa) and four proteins of the third larval stage (L3; 92, 78, 58, and 24 kDa). The immunoblots indicated that stage-specific proteins of the homogenates were recognized. Three stage-specific proteins of L3 larvae (150, 135, and 125 kDa) and three proteins typical to the adult worm (100, 82, and 67 kDa) were identified. The majority of the worm proteins elicited an IgG response. IgE synthesis was induced by living and dead parasites and was directed towards four proteins (190, 150, 125, and 98 kDa). Three proteins additionally induced an IgG or IgM antibody response. The immune response as shown by the immunoblotting technique seems to be directed towards (1) antigens that are present for the duration of an infection and (2) stage-specific antigens that are expressed for only a short time during the life cycle of the parasite.