DIAGNOSTIC POTENTIAL OF FRACTIONATED BRUGIA-MALAYI MICROFILARIAL EXCRETORY SECRETORY ANTIGEN FOR BANCROFTIAN FILARIASIS/

Due to the non-availability of sufficient parasite material from Wuche reria bancrofti, a heterologous filarial antigen from Brugia malayi ha s been investigated for the diagnosis of bancroftian filariasis. B. ma layi microfilarial excretory/secretory antigen (BmmfES) effectively in hibited the binding of circulating filarial antigen fractions (CFA(2)- 1, 9, 11 and 12) from microfilaraemic cases, and of W. bancrofti micro filarial excretory/secretory antigen, to the immunoglobulin G (IgG) fr action of anti-filarial serum immunoglobulins. BmmfES was separated by ion-exchange chromatography on DEAE cellulose into 2 fractions, BmE D E1 and BmE DE2. BmE DE1 was marginally superior to whole BmmfES and Bm E DE2 in detecting filarial IgG antibodies in human sera. 230 human se ra from different groups of patients were screened against BmE DE1, wh ich detected specific IgG in 83% of sera from microfilaraemic donors, 83% of sera from patients with clinical filariasis, 17% of sera from n ormal residents of an endemic area, and in none of the sera from perso ns living in a non-endemic area. The assay system using BmE DE1, with a sensitivity of 83% and specificity of 83%, should be very useful in detecting microfilaraemia, particularly in active clinical infections where the parasite is usually not seen.