ヒト口腔扁平上皮癌細胞に対するモノクローナル抗体の作製

抄録

Three monoclonal antibodies (MoAb), 1 F 9, 1 G 5 and 3 B 4, were produced by fusion of spleen cells of a BALB/c mouse immunized with Ca 9-22 cell from human squamous cell carcinoma of gingiva and murine myeloma cells SP 2/o.They were screened by 51Cr release assay of complement dependent cytotoxicity.Their isotypes were all IgM which recognized the cell surface antigens.Five MoAbs, 1 B 11, N 2, N 4, N 18 and 4 B 3, were prepared against NA cell from human tongue squamous cell carcinoma by the same procedure, but they were screened by radioimmunoassay using 125I-protein A.All MoAbs had isotypes IgG and only four recognized their antigen in the cytoplasm.N 4 recognized the antigen existing in both cytoplasm and cell membrane.
The reactivity of each MoAb to various cells and tissues was analyzed by immunostaining method.They were separable into three groups by the cell specificity, i.e.the first group including 1 F 9, 1 G 5, and 4 B 3 reacted to all squamous cell carcinoma cells tested but not to the normal diploid fibroblast WI 38.The second group comprising of 1 B 11, N 2, N 4 and N 18 was reactable to both squamous cell carcinoma cells and WI 38.The third group of 3 B 4 reacted to only Ca 9-22 used as the immunogen.From the study using paraffin embedded tissues including oral cancers and normal tissues, it was revealed that 1 F 9 and 1 G 5 stained the cell membrane of the cancer nest in squamous cell carcinoma and the prickle cell layer in the oral mucosa.The second group of MoAb, 1 B 11, N 2, N 4 and N 18, stained both parenchymal and stroma cells simultaneously.3 B 4, interestingly, showed different reactivity between individuals, namely in a positive case it stained not only the normal and malignant cell of squamous epithelial origin but also endothelial cells and erythrocytes in the stroma.However, in a negative case it did not stain any type of cell, suggesting that 3 B 4 may recognize an antigen related to the blood group.