ANALYSIS AND DIAGNOSTIC USE OF BRUGIA-MALAYI ADULT ANTIGEN IN BANCROFTIAN FILARIASIS

Detergent-soluble antigens of Brugia malayi adult worms (BmA SDS S Ag) were analysed for their antigenic activity and potential use in diagn osis of bancroftian filariasis. Analysis of SDS-PAGE fractions of BmA SDS S Ag against antifilarial antibodies, that is, human filarial seru m immunoglobulin G and anti BmA SDS S Ag antibody, revealed two active antigen fractions: BmA-6 and BmA-9. Antibodies raised to BmA-6 and Bm A-9 were tested with antigens isolated from infected human body fluids such as circulating filarial antigen (CFA(2)), urinary filarial antig en (UFAC(2)) and hydrocele fluid antigen (HFA). Both antibodies showed high reactivity with CFA(2)-1, 6 and 9 as well as UFAC(2)-5, 6 and 9 antigenic fractions. In immunoblotting studies, anti BmA-6 antibody de tected specific antigens of high microfilaraemic reactivity such as 12 0, 54, 26 and 22 kDa. In inhibition ELISA using anti BmA SDS S Ag anti body and antigen fraction BmA-6, filarial antigen was detected in 85% of microfilaraemic, 35% of clinical filarial and 20% of endemic normal sera samples. When anti BmA SDS S Ag antibody and BmA-9 were used, 80 % of microfilaraemic, 35% of clinical filarial and 25% of endemic norm al sera showed positive reaction for filarial antigen. The analysis of urine samples showed the presence of filarial antigen in 76 and 72% o f microfilaraemic cases using BmA-6 and BmA-9 fractions respectively w hile only 20% of endemic normals were positive using both the antigen fractions. High inhibitory antigen titre was noticed against BmA-6 ant igen in microfilaraemic sera. BmA-6 was found to be comparatively more sensitive in the detection of active bancroftian filarial infection.