ANTIBODY ISOTYPE RESPONSES TO ANTIGENS OF ASCARIS-LUMBRICOIDES IN A CASE-CONTROL STUDY OF PERSISTENTLY HEAVILY INFECTED BANGLADESHI CHILDREN

Antibody responses to Ascaris lumbricoides worm antigens were examined by ELISA in a case-control study of 2 groups of Bangladeshi children, one of which had been shown over a period of 12 months to be consiste ntly lightly infected (controls) and the other consistently heavily in fected (cases). The children showed a wide range in intensity of infec tion; children identified as cases were on average 4 times more heavil y infected than the controls. There were no significant differences in weight, height, mid-upper arm circumference and skinfold thickness be tween the case or control subjects at the time blood samples for analy ses by ELISA were collected. Children with repeatedly heavy infections with A. lumbricoides had higher concentrations of antibody isotypes t o the antigens of A. lumbricoides than children who are repeatedly lig htly infected. IgG1, IgG4 and IgE to worm antigens occurred in signifi cantly higher concentrations in heavily infected subjects. This sugges ts that these antibody responses simply reflect the intensity of infec tion and may not play a significant role in protecting against heavy i nfections.