Immunolocalization of Disorganized Muscle Protein-1 in Different Life Stages of Human Lymphatic Filariid, Brugia malayi

PURPOSE: We recently identified disorganized muscle protein-1 of Brugia malayi (DIM-1bm) as a vaccine candidate for human lymphatic filariasis. The present study was aimed at investigating the localization of DIM-1bm in the life-stages of B. malayi to identify the tissue target of vaccine action. METHODS: Recombinant DIM-1bm (rDIM-1bm) was prepared and antibodies were raised in BALB/c mice. Immunoblots of SDS-PAGE resolved B. malayi infective 3rd stage larvae (L(3)) and adult worm antigens and rDIM-1bm were prepared and reacted with anti-rDIM-1bm sera. Sections of adult female worms and whole-mount preparations of L(3) and microfilariae (mf) were stained by immunofluorescence using rDIM-1bm antibodies and Alexa Fluor 488 labeled secondary antibodies, and examined under a confocal microscope. RESULTS: Immunofluorescence staining showed that DIM-1bm is localized mainly in the subcuticular muscle layer in the L(3) and the adult worms; no fluorescent signal could be detected in mf. CONCLUSION: The localization of DIM-1bm in the parasites’ muscle layer suggests that the immunoprophylactic efficacy of DIM-1 is evidently due to immobilization of the parasite and its subsequent immune elimination.