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 diagnosis of bancroftian filariasis. Analysis of SDS-PAGE fractions of BmA SDS S Ag against antifilarial antibodies, that is, human filarial serum 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 BmA-9 were tested with antigens isolated from infected human body fluids such as circulating filarial antigen (CFA2), urinary filarial antigen (UFAC2) and hydrocele fluid antigen (HFA). Both antibodies showed high reactivity with CFA2-1, 6 and 9 as well as UFAC2-5, 6 and 9 antigenic fractions. In immunoblotting studies, anti BmA-6 antibody detected specific antigens of high microfilaraemic reactivity such as 120, 54, 26 and 22 kDa. In inhibition ELISA using anti BmA SDS S Ag antibody 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 normal sera showed positive reaction for filarial antigen. The analysis of urine samples showed the presence of filarial antigen in 76 and 72% of microfilaraemic cases using BmA-6 and BmA-9 fractions respectively while only 20% of endemic normals were positive using both the antigen fractions.(ABSTRACT TRUNCATED AT 250 WORDS)