A STUDY OF APOPTOSIS IN THE HUMAN PALATINE TONSIL

Apoptosis is a morphological involution caused by a cellular suicide p rogram which is associated with programmed cell death. Several reports have shown that Fas antigen mediated apoptosis and death of immunocyt es in lymphoid tissues are induced through apoptotic mechanisms. The p resent study was designed to investigate apoptotic cells in human pala tine tonsils by using in situ end-labeling (ISEL) technique and flow c ytometric analysis with anti-Fas antibody. The ISEL technique showed t hat a number of apoptotic cells were present in the subepithelial area of the tonsil. Flow cytometric analysis showed that the number of ant i-Fas positive cells in the tonsil was larger in adults than in childr en. Further, tonsillar lymphocytes were examined for mRNA expression o f the Fas antigen using reverse transcription polymerase chain reactio n (RT-PCR) method. Fas mRNA expression was confirmed in tonsillar lymp hocytes. The results suggest that apoptosis may be related to morpholo gical and immunologic involutions of the tonsil.