BIOLOGICAL-ACTIVITY AND DIAGNOSTIC USE OF DETERGENT SOLUBLE-ANTIGENS FROM SETARIA-DIGITATA

Filarial parasite, responsible for filariasis is known to remain in th e host for long periods of time. A 29 kDa protein isolated from Setari a digitata by gel electrophoresis and electroelution of detergent solu ble surface antigens showed a 70% inhibition of the cell mediated immu ne response. On evaluation of its diagnostic application, the same pro tein was found to be very sensitive in detecting antibody at an antige nic protein concentration as low as 1 ng per mu l. The cross reactivit y of surface antigen with bancroftian filarial patient's sera was test ed by Dot-ELISA and ELISA. Both the antigen as well as antibody detect ion tests showed 100% positivity with all types of filariasis cases. I t did not produce any positive reaction with non-endemic control sera. However, a proportion of endemic normal subjects showed positivity an d this is attributed to the fact that people in endemic areas are expo sed to infective mosquito bites. The biological property of inhibition and 100% positivity of filariasis cases in both antibody and antigen detection tests point towards the bifunctional nature of the surface p roteins before and after release. The same may be happening under norm al conditions also, perhaps at a much lower rate.