Transformation of Lymphocytes from Animals Sensitized to Trichinella Spiralis

Abstract

Abstract Guinea pigs sensitized once or hypersensitized four times at bi-weekly intervals in the footpads with Trichinella extract, emulsified in complete adjuvant, were examined for serum antibody content and tissue cellular changes. The following modifications were found in the two groups. Those sensitized, when homologously skin-tested at 1 week, showed a typical delayed hypersensitivity reaction, whereas the hypersensitized group, when similarly skin-tested 2 weeks after the fourth injection, showed an accelerated reaction which appeared somewhat like the Arthus type. The difference in skin reactivity of the two groups was not associated with the kind of cells present at the site but rather with a marked difference in antibody content of the serum and in the absolute and relative number of mononuclear cells present at the site and in the lymph nodes. The cellular content of the subcutaneous tissue at the site of the skin test was characteristic of delayed hypersensitivity in both groups as evidenced by a predominant perivascular infiltration of mononuclear cells. The hypersensitized group, as compared with the sensitized group, showed 1) more circulating antibody, as measured by passive cutaneous anaphylaxis and the precipitin ring test, 2) a greater proportion, as compared to small lymphocytes, of mediumand large-sized lymphocytes, macrophages, plasma cells and eosinophils, 3) a greater antibody content per mononuclear cell in the lymph nodes, as measured by fluorescent staining, and 4) more deaths (50% vs 0%) when tested by active systemic anaphylaxis. The four differences between the sensitized and hypersensitized groups were evident whether the groups were homologously skin-tested or not. Primed lymphocytes when incubated for 5 days in vitro with the Trichinella antigen, however, showed more transformation into “blast-like” cells in the skin-tested as compared with the non-skin-tested groups of both sensitized and hypersensitized guinea pigs; but there was no difference between the sensitized and hypersensitized groups.