Fine Structure of Lymphocytes Sensitized to Trichinella Spiralis Antigen

Summary

Guinea pigs were sensitized with Trichinella spiralis antigen combined with complete adjuvant and skin-tested 7 days later. Cells from lymph nodes were processed for electron microscopy before or after in vitro cultivation with homologous antigen. Lymphocytes from sensitized animals were usually larger and had a greater nucleo-cytoplasmic ratio than unstimulated lymphocytes. The nucleus was eccentric with patches of compact chromatin around the periphery; the cytoplasm had many ribosomes and a few scattered channels of endoplasmic reticulum, mitochondria, Golgi bodies and some dark granules. After incubation for 5 days with homologous antigen, about 15% of the cells were greatly enlarged. The most striking cytoplasmic change was in the ribosomes; these were more numerous and dispersed, either singly or in rosettes. Other changes included increase in lamellae of the ergastoplasm and mitochondria. The nucleus was mainly round with lighter nucleoplasm and diffused chromatin. In contrast, unstimulated lymphocytes had a nucleus with compact chromatin and a thin rim of cytoplasm containing ribosomes, few mitochondria, Golgi bodies and few cisternae of endoplasmic reticulum. The ultrastructure of unstimulated lymphocytes incubated with antigen for 5 days did not differ from those cultured without antigen or from freshly isolated lymphocytes from unsensitized donors.