Cellular Immunity to <i>Nippostrongylus brasiliensis</i> in the Rat

Abstract

Purified peritoneal exudate cells from rats infected once or twice with N. brasiliensis have been examined for the ability to produce the migration inhibitory factor (MIF) in vitro when cultured with living third-stage larvae. It was found that, 1 week after a single infection with 2,500 larvae, MIF production was readily demonstrable. The amount of detectable MIF in the culture supernatants tended to increase during the 2nd week but declined to below significant levels 3 weeks after infection. From the 4th to 8th week of infection, MIF production was highly variable. This was also the case for animals infected twice with 2,500 larvae where the interval between infections varied between 1 and 8 weeks, with 2 weeks between the second infection and harvesting of cells for culture. Cells able to produce MIF in culture could be inhibited to some extent by pre-treatment with serum from rats infected for 3 weeks, suggesting the presence of a serum inhibitor.