VACCINATION GENERATES SERUM-MEDIATED PROTECTION AGAINST ONCHOCERCA-LIENALIS-MICROFILARIAE IN THE MOUSE

Mice vaccinated with an aqueous extract of Onchocerca lienalis microfi lariae (mf) plus adjuvant exhibited 51% protection against challenge w ith live mf. Protection was ablated by prior treatment of the extract with heat or proteinase K, indicating the involvement of proteinaceous epitope(s). A 54% level of protection was conferred on naive mice by passive transfer of serum from vaccinated donors, suggesting that host resistance was principally mediated by humoral components of the immu ne response. In contrast, the protection induced by sensitization of m ice with living mf is transferable with cells, but not serum. Western blot data reveal different antigen recognition profiles for serum anti bodies from these two groups of mice. These results indicate that vacc ination and infection activate distinct protective mechanisms against Onchocerca mf in the mouse.