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

Abstract

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