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 I and C I ) with muscle larvae. Lung tissue extracts (LTE) and lung cell suspension (LCS) were obtained. PD I had lower titres of anti‐NBL antibodies in LTE than C I . In ADCC assays using control cells, NBL mortality percentage was lower with LTE from PD I than LTE from C I ( P  < .01). In assays using control cytotoxic sera, ADCC was exerted by LCS from C I at all days post‐infection (p.i.), but only by LCS from 13 days p.i. from PD I . ADCC assays combining LTE and LCS from the same group showed a lower response for PD I than for C I ( P  < .0001). LCS from PD I contained lower numbers of neutrophils, eosinophils and FcεRI + cells than C I . PD may diminish ADCC activity against T spiralis NBL in lungs through alterations in specific antibodies and effector cells.