Passage of host immunoglobulin G from blood meal into hemolymph of selected mosquito species (Diptera: Culicidae)

Passage of ingested host antibody (IgG) from the digestive tract into the hemolymph was examined in six species of mosquitoes. Mosquitoes were fed upon either an immune host (typhus-immune rat) or nonimmune host (control) rat. At selected intervals after ingestion, hemolymph samples and midgut contents were collected and assayed for specific rat IgG using indirect immunofluorescent assay techniques. Within 3 h after ingestion, antibody appeared in the hemolymph of Anopheles stephensi Liston, An. gambiae Giles, and An. albimanus Wiedemann. In these species, the persistence of host antibody was longer in the gut (24–48 h after ingestion) than in the hemolymph (18–24 h after ingestion). Host antibody was detected at low levels in the hemolymph of Culex pipiens L. at 3 h after ingestion but not thereafter. Antibody passage was undetectable in An. freeborni Aitken and Aedes aegypti (L.) Those species that exhibited marked antibody passage stayed on the host and fed for extended periods of time while simultaneously excreting red fluid from the anus (prediuresis). Mosquito species not displaying antibody passage fed relatively quickly, left the host, and exhibited little, if any, prediuretic activity while feeding.