An enterotoxic activity of 18-20 kDa Cryptosporidium parvum secretory coproantigen (CCA 18-20 kDa).

An 18-20 kDa Cryptosporidum coproantigen (18-20 CCA), had been detected in the stool of infected humans and calves. A purified, electroeluted and concentrated 18-20 kDa antigen was tested in Ussing chamber, and electric parameters were tested before and after the addition of this antigen. A significant increase in the short circuit current (Isc) was detected. The enterotoxic effectof 18-20 kDa CCA, was time and dose dependent, heat labile, and Cl- dependent. The detected change in the short circuit current was not detected when the 18-20 kDa antigen wa incubated with its monospecific antibodies. These results indicate an enterotoxic activity of the 18-20 kDa antigen secreted from the released parasite and detected in stool of infected humans and calves. Additionally, they may help in developing an appropriate anti-secretory therapy for the intractable diarrhoea caused by cryptosporidiosis.