INDUCTION OF THYMOCYTE APOPTOSIS IN MICE BY YERSINIA-ENTEROCOLITICA PRODUCTS

In-vivo administration of the culture supernates from Yersinia enteroc olitica resulted in thymus atrophy in C3H/HeJ mice, known to be lipopo lysaccharide (LPS)-non-responders. The thymocytes underwent apoptosis as characterised by fragmented DNA ladders on agarose gel electrophore sis, a cell death detection ELISA and a morphological study by the TUN EL reaction. As a control, LPS treatment did not induce thymocyte apop tosis in C3H/HeJ mice. Flow cytometric analysis indicated that thymus atrophy was due predominantly to the deletion of CD4(+)CD8(+)T cells. When cells were undergoing apoptosis, an elevation in the percentage o f T-cell receptor (TCR)-cells alpha beta(high)was observed at 24 h, wh ich was correlated with the increase in the percentages of cells expre ssing high levels of the V beta 6 and V beta 8 TCR. Gel electrophoreti c analysis demonstrated the presence of protein bands with mol. wts ra nging from 17 to 65 kDa in Y. enterocolitica culture supernates.