Antibody response of definitive hosts against antigens of two life stages of the neuropathogenic schistosome XXXX .

@entity4186 @entity1 @entity19 @entity21933 @entity281 @entity74 @entity1909 @entity912
BACKGROUND: The nasal avian schistosome @entity21933 spends part of its intravertebrate period of life within the central nervous system. Migration of the parasites can be accompanied by @entity74 or @entity912 in natural definitive hosts ( @entity4186 ) and even in laboratory mammals. Cercariae are also able to penetrate @entity1 skin and induce @entity1909 . While the cellular and antibody responses against cercariae and migrating schistosomula have been investigated in @entity19 , little is known about immune reactions in birds. This study first describes the dynamics of antibody response in infected @entity4186 and identifies frequently recognized antigens that may serve as diagnostic markers of @entity281 by @entity21933 . METHODS: Groups of 35 @entity4186 and 10 @entity4186 were exposed to different doses of @entity21933 cercariae. Sera were collected at predefined time intervals and tested by ELISA for the presence of specific anti-cercarial IgY and IgM. Antigens recognized by the antibodies were identified on Western blots of cercariae and schistosomula. The applicability in immunodiagnostics was statistically evaluated by expression of specificity and sensitivity values for individual antigens. RESULTS: In ELISA, the levels of anti-cercarial IgM peaked on day 15 pi. Increased production of IgY associated with the later phases of @entity281 was observed in most individuals around 20 dpi and culminated 30 dpi. The time course of antibody response did not differ among experimental groups, variations were only observed in the levels of specific IgY which depended rather on the age of @entity4186 at the time of @entity281 than on the infectious dose. On Western blots, 40 cercarial and 7 schistosomular antigens were recognized by IgY from infected @entity4186 . Among them, 4 cercarial antigens of 50, 47, 32 and 19  kDa provided the most sensitive and specific reactions. CONCLUSIONS: Antigens of cercariae and schistosomula elicited distinct antibody response in @entity4186 , which correlated positively with the age of animals at the time of @entity281 . Several antigens originating in cercariae and fewer in schistosomula were recognized by IgY with diverse sensitivity and specificity; only a few seemed to be common to both stages. Four of them were considered as the most promising candidates for immunodiagnostics.
