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Protective immunity in human Bancroftian filariasis: inverse relationship between antibodies to microfilarial sheath and circulating filarial antigens
Author(s) -
Ravindran B.,
Satapathy A.K.,
Sahoo P.K.,
Babu Geddam J.J.
Publication year - 2000
Publication title -
parasite immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 75
eISSN - 1365-3024
pISSN - 0141-9838
DOI - 10.1046/j.1365-3024.2000.00347.x
Subject(s) - biology , antibody , filariasis , immunology , antigen , wuchereria bancrofti , immunity , immune system , helminths
The existence and the nature of protective immunity in human filariasis continues to be a subject of intense debate. While there is no broad consensus on functional immunity against larval and adult stage parasites, anti‐microfilarial immunity has been demonstrated to be mediated by antibodies to the microfilarial sheath. In the present study, circulating filarial antigens (CFA), a marker of active filarial infection in human Bancroftian filariasis, was found to be inversely associated with antibodies to microfilarial sheath in a cohort of 411 subjects representing all categories of filariasis across the clinical spectrum of the disease. Approximately 80% of humans of all age groups (5–65 years) were found to have either CFA or anti‐sheath antibodies. The inverse relationship observed between these two parameters was found to be independent of the clinical manifestation; both symptomatic and asymptomatic cases were found to display similar inverse association between CFA and anti‐sheath antibodies. The prevalence of anti‐sheath antibodies in the paediatric group was found to be very high as compared to adults; 78% of children below the age of 10 years tested positive for anti‐sheath antibodies although the mf rate and CFA rate were only 4.5% and 22.7%, respectively, in this age group, indicating that developing larvae or juvenile adult stage parasites could have been the source of antigenic stimulus for induction of antibodies to the microfilarial sheath .