Identification of sex-linked antigens ofSchistosoma mansoni by immunoelectrophoresis and immunoblotting.

Immunoelectrophoresis and immunoblotting techniques, using sera from hyperimmune rabbits and infected mice, were used to analyze antigens ofSchistosoma mansoni. A comparison was made between the antigenic composition of adult male and female worms, isolated from monosexually and bisexually infected hamsters. A large number of female-specific and a few male-specific antigens were detected. The antigenic composition of females isolated from monosexually infected hamsters was shown to be very different from that of paired females. The presence of a major female-specific antigen with an apparent molecular weight of 32 kd in paired females only, suggests that synthesis of this antigen by female worms is initiated by the male partner. Analysis of the humoral immune response of mice receiving bisexual or monosexual infections showed that both mono- and bisexually infected mice develop a major humoral immune response to a 36-kd polypeptide antigen. A response to a major polypeptide antigen with an apparent molecular weight of 60 kd was observed in bisexually infected mice only. No antibodies reactive with this 60-kd polypeptide are formed during mon-osexual infections with either male or female worms. The 60-kd polypeptide was, however, present in monosexually reared females. This presence, and the presence in bisexually reared males, suggests a transfer of this antigen from females to males.