Detection and localization of antibody ingested with a mosquito bloodmeal

Mouse immunoglobulins were found to persist in Aedes aegypti (L.) mosquito bloodmeals for 2-3 days after ingestion. Immunoenzyme labelling revealed mouse antibody specifically bound to the mosquito midgut epithelium after ingestion; immunogold labelling of thin sections revealed mouse antibody within the cytoplasm of the microvilli on the midgut epithelium. Ingested mouse antibody was not conclusively demonstrated bound to tissues outside the gut, though antibody was detected in mosquito haemolymph using a sensitive ELISA test. Possible mechanisms by which antibody may cross mosquito gut barriers and actions that in vivo antibody:antigen reactions may have on these bloodfed insects are discussed.