Chitosan effects on T[CD4plus, CD8plus] lymphocytes and macrophages during experimentally induced trichinosis in mice

The study involved mice of an inbred CFW line from the author’s own culture conducted according to the street light method (Lane Petter and Pearson 1971). All the animals, aged about 3 months and weighing 20 g each, were infected per os with 200 T. spiralis larvae per mouse. A total of 76 mice, divided into two groups, were used. Group I constituted the control and consisted of T. spiralis-infected mice, while Group II consisted of chitosan (chitosan adipinate)-treated mice receiving a dose of 0.4 mg per mouse, administered intra-peritoneally for 20 days (6 days prior to infection until day 13 post-infection). Four mice of each group were sacrificed by decapitation on invasion day 7, 14, 21, 28, 35, 42, and 60. Sections of the jejunum and mandibular muscle were used to prepare populations of cells involved in the inflammatory infiltration. The populations selected were the T (CD4+ and CD8+) lymphocytes and macrophages. The first were identified with immunofluorescence, using labelled monoclonal antibodies, while identification of the latter proceeded immunoenzymatically, with non-labelled monoclonal antibodies. In addition, the infected animals in each group were examined for the presence of parasites: on day 7, 10, 14, and 21 post-infection, the intestinal parasites were counted, while, the muscle-dwelling larvae being enumerated on day 60 post-infection. In this study, the macrophage count in the jejunum mucosa basement membrane of the chitosan-treated mice increased until day 21 post-infection and remained, until the observations were terminated, at a level higher than that in the control. On the other hand, the transversely striated muscles revealed, in addition to T CD4+ and T CD8+ lymphocytes, a stronger macrophage mobilisation throughout the period of observations. The chitosan-treated mouse jejunum were also a site of a faster removal (“expulsion”) of adult parasites than in the control, the muscle larval count in those mice being clearly lower than in the control.