PROTECTIVE IMMUNITY AGAINST MULTIPLE CHALLENGES OF BRUGIA-PAHANGI IN MONGOLIAN GERBILS INDUCED BY DRUG-ABBREVIATED INFECTION

Protective immunity against multiple challenge infections was examined in Mongolian gerbils after a drug-abbreviated infection with Brugia p ahangi. The gerbils treated with mebendazole (MBZ) during the late pre patent period (7-9 weeks of postinfection) were challenged with 5 inoc ulations of 50 infective larvae of B. pahangi at 4-week intervals. The worm burden was significantly reduced 68.6% (19.0 in average number) to that of controls (60.6) and was accompanied with enhanced eosinophi l responses 1 week after each challenge. MBZ-treated gerbils suppresse d microfilaremia almost completely after the challenge infections.