Immunohistochemical study of schistosomal soluble egg antigen in male genital organs of Schistosomiasis mansoni infected mice.

Seventy Swiss outbred mice were used for demonstration of circulating soluble egg antigen (CSEA) in serum and testes of S. mansoni infected mice and to study the possible role of this antigen (CSEA) in the pathogenesis of reproductive organ lesions using two recently described monoclonal antibodies to repetitive carbohydrate epitopes of S. mansoni SEA (114-5B-1A and 114-4D12-A). Ten mice as a control group and the other 60 mice were infected with 100 S. mansoni cercariae per mouse by subcutaneous injection. One group was sacrificed in each of 6,8,10,12,14 and 16 weeks post-infection (P.I.) while control mice were killed at one time. The sacrificed mice were bled and their sera were used for detection of CSEA by ELISA. The testes were dissected and paraffin blocks for histopathological study and indirect immunofluorescence technique. The mean level of CSEA in the serum of infected mice started to appear 6 weeks P.I. and gradually increased till 16 weeks P.I. This was coincided with the appearance of the fluorescent deposits in blood vessels of testis at 8 week P.I. and later in the stroma of testis from the 10th week onwards. These data together with histopathological findings with absence of egg in all examined testicular sections emphasize the possible role of CSEA in pathogenesis of such lesions.