Abstract: Abstract: The dynamic expression of the apoptotic gene-Fas/FasL in immunity organs of Gushi chickens was studied by using immunohistochemistry technology and Leica Microsystems, and its physiological significane was disscussed. The results showed that the expression of Fas in different immunity organs were observed, however, the number of the positive Fas-cells were different between different developmental stages. The positive Fas-protein was found in cell membrane, cytoplasm, but not in nucleus of lymphocytes. The positive Fas-cells were dispersed (or in clusters), and distributed in different places for different immunity organs. The majority of positive Fas-cells, in bursa, were observed in lamina propria of mucous membrane near epithelium and areas between lymphoid nodules, edges of lymphoid nodules, and a few in inner of lymphoid nodules. In thymus, the positive Fas-cells localized mainly in thymic medulla, and few in thymic cortex. The positive Fas-cells, in spleen, were found predominantly in red pulp, marginal zones, and the surronding areas of splenic nodules and periarterial lymphatic sheath, few in splenic nodules and periarterial lymphatic sheath. The expression of FasL in immunity organs of Gushi chickens is similar to Fas, but, the positive FasL-cells is less than Fas. All results mentioned above indicate that the apoptotic gene-Fas/FasL participates in the regulation of apoptosis of thymocytes and lymphocytes in immunity organs of Gushi chickens, and it is important for the stability of immunity organs.

Key words: Expression of apoptotic gene, FasL, Fas, Apoptosis, Gushi chicken, Immunity organ, Immunohistochemistry, Expression of apoptotic gene, FasL, Fas, Apoptosis, Fas, FasL, Expression of apoptotic gene, Immunohistochemistry, Immunity organ, Gushi chicken, Apoptosis