INDUCTION OF APOPTOSIS REDUCES IMMUNOGENICITY OF HUMAN T-CELL LINES IN MICE

Apoptotic cells, e.g. postinflammatory neutrophils, were reported to b e engulfed by phagocytes without induction of an inflammatory response . We investigated the humoral immune response of BALB/c mice after rep eated injection of viable or apoptotic human T cells. Following interl eukin-2 (IL-2) deprivation, phytohaemagglutinin (pHA)IL-2 expanded hum an T-cell lines were irradiated with UV-B light to induce apoptosis, c onfirmed by propidium iodide staining of Triton X-100-lysed cells. Ind irect immunofluorescence was used to detect antilymphocyte antibodies 7 days after each injection. We found high levels of antilymphocyte an tibodies in all animals immunized with viable T cells, whereas animals injected with apoptotic cells showed a significantly reduced humoral immune response. We conclude that apoptotic cells induce poor xenoreac tive T-cell responses when compared with viable cells.