Suppression of microfilaraemia inLitomosoides cariniiinfections in cotton rats by vaccination with adult worm homogenate

Abstract

Twenty cotton rats were injected with a homogenate of adult male and female Litomosoides carinii prepared by freeze-thawing the worms in phosphate-buffered-saline followed by mechanical treatment in a Potter-Elvejham homogenizer. Intramuscular injections including Freund's complete adjuvant were made into rats which were subsequently quantitatively exposed to infection with L. carinii in Liponyssus bacoti. There was no development of a microfilaraemia between 50 and 100 days post-infection in any of the ‘vaccinated’ cotton rats despite the presence of living adult male and female worms and microfilariae in the pleural cavity. In all the control animals a microfilaraemia developed which persisted for up to 100 days after infection.