Antigen density tumor cells

CD56 (also known as neural cell adhesion molecule) is expressed on the cell surface of a number of different tissues including natural killer cells, glial and neurons. This antigen may be demonstrated on monocytic and myeloid leukemias, plasma cell dyscrasias, natural killer cell lesions, neural and astrocytic tumors as well as tumors with neuroendocrine differentiation. Antigen density on hematopoietic tumors tends to be at a lower level than on non-hematopoietic lesions and the validation with flow cytometry determination for this antigen is recommended. 

Inadequate performance may result from lack of antigen specificity, e.g., tumor-specific antigens are often differentiation antigens which also occur, although in a lower density on nontarget cells (Poste, 1984). 

Nores GA, Dohi T, Taniguchi M, Hakomori S Density-dependent recognition of cell surface GMj by a certain anti-melanoma antibody, and GM3 lactone as a possible immunogen Requirements for tumor-associated antigen and immunogen. J. Immunol. 1987 139 3171-3176. 

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