MHC and non-MHC-restricted recognition of filarial surface antigens in mice transplanted with adult Brugia malayi parasites

We describe here the genetic control of humoral responses to filarial nematode Ag elicited by live adult Brugia malayi parasites in mice. Inbred and congenic mice of two different MHC haplotypes, H-2k and H-2d, were examined. Serologic analysis showed that the humoral responses to the major surface 29-kDa glycoprotein of adult parasites and a 40-kDa Ag from the surface of the microfilarial stage were restricted to mice with H-2k alleles (B10.BR, CBA/Ca, and CBA/N), whereas mice of the H-2d haplotype (B10.D2/n and BALB/c) were nonresponsive to these Ag. Conversely, internal adult Ag of molecular mass of 24 and 66 kDa were recognized only by animals with the H-2d haplotype. Apart from MHC-restricted recognition, the level of responses to phosphorylcholine and to a 15-kDa adult surface molecule were found to be influenced by non-MHC genes. A sharp restriction was also observed to an adult surface Ag complex of 17 to 200 kDa, which was recognized only by BALB/c mice. Thus, multiple examples of both H-2 and background genetic effects on the immune response to distinct filarial Ag can be found.