Antibodies to Anopheles culicifacies Salivary Glands Encumber Vector Competence to Plasmodium vivax

Anopheles culicifacies A and C are responsible for 65-70% of malaria cases in India. Species B is least susceptible to parasite and plays very little role, if at all, in the malaria transmission. Three sets of rabbits were immunized with the salivary gland proteins from these three members (A, B and C). High titer antibodies were detected in the sera when characterized by in vitro ELISA. Western blotting and in vivo ELISA were conducted to gauge the cross reactivity of these antibodies with other tissues as well as salivary glands from other sibling species. Salivary glands and midgut exhibited highest cross reactivity. 97 kDa polypeptide was recognized exclusively by antibodies against salivary glands of species-A and C (primary vectors). Similarly, two immunogenic polypeptides (29 and 21 kDa) were present only in species-B. Fecundity was reduced significantly (37%) and number of oocysts per infected mosquito was reduced by 69% in the group of mosquitoes that ingested anti-salivary gland antibodies along with infected blood meal. Proportion of infected mosquitoes was significantly low as compared to control.