BACKGROUND: CD43 is a sialoglycoprotein that is highly expressed on most leukocytes, except on B lymphocytes and dendritic cells. CD43 has been reported to be involved in the adhesion and apoptosis of lymphocytes. Although the aberrant expression of CD43 antigen in non-lymphoid tissues has been reported, the expression of the CD43 antigen in gastrointestinal malignancies is not well studied. Here, we studied the expression of CD43 in colon adenocarcinoma using the anti-CD43 monoclonal antibody developed in our laboratory. METHODS: Thirty patients who had undergone surgical resection for colorectal carcinoma were recruited. The expression of CD43 molecule was determined by analyzing the formalin-fixed, paraffin-embedded specimens immunohistochemically using our newly developed anti-CD43 mAb (K06). The results obtained by the immunohistochemical analysis correlated to the clinicopatho-logical parameters. RESULTS: The expression of CD43 were found in 20 out of 30 colorectal carcinoma cases. The expression of CD43 antigen is higher in well differentiated adenocarcinomas than poorly or moderately differentiated adenocarcinomas. CONCLUSIONS: The new anti-CD43 mAb might be helpful for the detection of the expression of CD43 on colorectal carcinoma cells. Further studies are required to assess the relationship between the CD43 expression and the colorectal carcinogenesis.
Adenocarcinoma ; Antigens, CD43 ; Apoptosis ; B-Lymphocytes ; Carcinogenesis ; Colon ; Colorectal Neoplasms ; Dendritic Cells ; Humans ; Immunohistochemistry ; Leukocytes ; Lymphocytes

CD43 (sialophorin, leukosialin) is a heavily sialylated surface protein expressed on most leukocytes and platelets including T cells. Although CD43 antigen is known to have multiple and complex structure, exact function of CD43 in each cell type is not completely understood. Here we evaluated the role of CD43 in Fas (CD95)-induced cell death in human T lymphoblastoid cell line, Jurkat. Crosslinking CD43 antigen by K06 mAb increased the Fas-mediated Jurkat cell apoptosis and the augmentation was inhibited by treatment with caspase inhibitors. Further, CD43 signaling of Jurkat cells induced Fas oligomerization on the cell surfaces implying that CD43 ligation have effects on early stage of Fas-induced T cell death. These also suggest that CD43 might play an important role in contraction of the immune response by promotion of Fas-induced apoptosis in human T cells.
Receptor Aggregation/immunology ; Jurkat Cells ; Humans ; Caspases/metabolism ; Apoptosis/*immunology ; Antigens, Surface/metabolism ; Antigens, CD95/metabolism/*physiology ; Antigens, CD43/metabolism/*physiology ; Antibodies, Monoclonal/metabolism