FREE-RADICAL GENERATION AND THE COURSE OF PRIMARY INFECTION WITH NIPPOSTRONGYLUS-BRASILIENSIS IN CONGENITALLY ATHYMIC (NUDE) RATS

The course of primary infections with Nippostrongylus brasiliensis was followed in nude (CBH/R nu/nu) and heterozygote (CBH/R nu/+) rats. In both nude and heterozygote rats peak egg production by N. brasiliensis occurred on days 7 and 8 post-infection. However, whereas in heterozygote rats egg production declined rapidly thereafter and ceased completely by day 14 post-infection, in nude rats high numbers of N. brasiliensis eggs were still seen on day 27 post-infection, when the experiment was terminated. In comparison with the nude rats, heterozygote rats had a 5-fold greater loss of weight by day 9 post-infection and a 4-fold higher incidence of diarrhoea. Furthermore, infected heterozygote rats became anaemic whereas uninfected rats and infected nude rats showed no evidence of anaemia. Free radical generation was measured in infected (9 days) and uninfected rats. Leucocytes from infected heterozygote rats were able to generate copious quantities of free radicals in response to N. brasiliensis whereas leucocytes from infected nude rats produced only slightly more free radicals than uninfected rats. Thus, worm rejection, weight loss, diarrhoea, anaemia and free radical generation in response to N. brasiliensis infection are all T-cell dependent events.