Cryptosporidium parvum:: identification and characterization of an acid phosphatase

Acid phosphatases are putative virulence factors in different pathogenic microorganisms. Acid phosphatases can also inhibit the respiratory burst of human neutrophils. In Cryptosporidium parvum, a protozoan parasitic, the study of enzymes is limited. In this paper, we report the presence of a membrane-bound acid phosphatase activity in C. parvum oocysts. The enzymatic activity was inhibited by protein tyrosine phosphatase inhibitors such as sodium orthovanadate, ammonium molybdate, and sodium tungstate and was not affected by protein serine/threonine phosphatase inhibitors such as okadaic acid and calyculin. Antibodies against the catalytic domain of human placental PTPase 1B cross-reacted with two molecules of 30 and 31 kDa present in membrane fraction of a Cryptosporidium oocyst homogenate. This is the first demonstration of acid phosphatase activity in Cryptosporidium.