ANTIBODY-RESPONSES TO LUCILIA-CUPRINA IN SHEEP SELECTED FOR RESISTANCE OR SUSCEPTIBILITY TO L-CUPRINA

Sheep bred for resistance (R) or susceptibility (S) to fleece rot and myiasis (blowfly strike) have been shown to differ in inflammatory res ponse to intradermal administration of blowfly (Lucilia cuprina) antig ens and artificial challenge. The current paper describes analysis of antibody responses to L. cuprina antigens in the R and S animals. Seru m antibody titres and specificities to larval antigens were examined a nd the specificity of wound exudate antibodies was also investigated i n animals artificially challenged with L, cuprina. Titres of L. cuprin a specific serum IgA, IgM, IgG(2) and IgG(1) were measured by ELISA, w hile specificities were examined on two-dimensional immunoblots of lar val homogenates. Exposure to L. cuprina stimulated the production of s pecific antibody in both R and S animals, however antibody titres did not differ between the R and S animals. There was large variation in a ntibody specificity between individual animals and some L, cuprina pro teins appear to be more frequently recognized by sera from either resi stant ol susceptible animals, however the recognition of a specific pr otein could not be solely attributed to the resistance status of the a nimal. It appears that resistance in these animals may be independent of serum antibody and is likely to be an innate response. Despite high levels of IgG in wound exudates, this antibody recognized few antigen s in comparison with serum from the same animal, suggesting that exuda te contains little functional antibody in comparison to serum.