Protein deficiency during Trichinella spiralis infection impairs lung immunity against newborn larvae.

The goal of this study was to analyse the effects of a protein-deficient (PD) diet on antibody-dependent cell-mediated cytotoxicity (ADCC) in vitro against newborn larvae (NBL) of Trichinella spiralis in the lungs of infected rats. Two groups of weaning Wistar rats received a PD diet (6.5% casein) and other two received a control diet (C, 20% casein). After ten days, one group of each diet was infected (PD and C ) with muscle larvae. Lung tissue extracts (LTE) and lung cell suspension (LCS) were obtained. PD had lower titres of anti-NBL antibodies in LTE than C . In ADCC assays using control cells, NBL mortality percentage was lower with LTE from PD than LTE from C (P < .01). In assays using control cytotoxic sera, ADCC was exerted by LCS from C at all days post-infection (p.i.), but only by LCS from 13 days p.i. from PD . ADCC assays combining LTE and LCS from the same group showed a lower response for PD than for C (P < .0001). LCS from PD contained lower numbers of neutrophils, eosinophils and FcεRI cells than C . PD may diminish ADCC activity against T spiralis NBL in lungs through alterations in specific antibodies and effector cells.