Benha M, J.
Vol. 11 No 1 Jan. 1994
HUMAN RESISTANCE TO REINFECTION
WITH SCHISTOSOMES
Specific IgE titres before and 3 months after praziquantel treatment
ALL El-Said Ali Ph.D and Hind Sheheen Ph.D*
Parasitology Department. Benhafaculty of Medicine, Zagazig University, and namru-3- Cairo", Egypt.
Abstract
The characterized feature of humoral immune response to schistosomal infection is the production of specific antibodies. Specific IgE assays by ELISA technique for schistosomal cases of low and high resistance to rein-fection showed that anti-soluble egg antigen (SEA) IgE and ana-soluble worm antigen preparation (SWAP) IgE titres are significantly higher among high resistant cases than that among reinfected (low resistant) cases before and 3 months after praziquantel treatment. IgE titres are not correlated with IgG titres among both groups. Anti-SEA IgG titre of resist¬ant cases significantly decreased, while anti-SWAP IgG significantly in¬creased among reinfected cases after praziquantel treatment. Reinfection susceptibility is.invariable among males & females. No correlation be¬tween intensity of infection (egg count) and IgE titres. High levels of spe¬cific IgE against different schistosomal antigens (SEA & SWAP) among high resistant cases demonstrate the role of IgE for host protection agai¬nst schistosomal reinfection.
Introduction somal infection (Rihet et ad.,
In endemic areas certain indi- 1991).
viduals have no sign of active in¬
fection inspite of daily contacts The resistance to reinfection af-
with infected waters, indicating ter chemotherapy can not be dem-
that these individuals exhibit a onstrated until the age of 12 years
high level of immunity to schisto- at earliest (Dunne et.al., 1992).
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