Abstract

Isolates of cryptosporidia from immunodeficient patients and from immunocompetent children suffering from diarrhoea were sources for preparation of antigens. Altogether, antigens from 21 isolates were obtained, 19 from children and 2 from AIDS patients. With one exception, all children were under 4 years old and most of them were between 1 and 2 years old. The probable source of infection was found in 11 cases. In 8 cases, as well as in both AIDS patients, the source of infection was not determined. The same groups of persons and the control group of healthy blood donors were examined serologically using ELISA with the antigen of bovine origin and positive sera were used for following experiments. Soluble and membrane-enriched antigens from oocysts were compared using polyacrylamide gel electrophoresis and electroimmunotransfer blots developed by human immune sera. While no differences were recorded in soluble antigens, two of the membrane-enriched antigens were missing (15.5 and 33 kD bands). While all isolates with a pattern typical for Cryptosporidium parvum were infective for neonatal mice, both isolates with missing bands were not infective for newborn mice in repeated experiments. The first of them was infective for chickens and was originally determined to be Cryptosporidium baileyi (Ditrich et al. 1991). However, the antigenic pattern differs from pattern of this species. The second isolate was infective for guinea pigs and its species classification remains uncertain.