The distribution of cell fusion capacity among several cell strains or cells caused by HVJ

The cell fusion capacities caused by HVJ of various kinds of cells of mammalian and fowl origin were determined quantitatively. All established tissue culture strains tested (seven strains from human, monkey, rabbit and mouse tissues), six mouse ascites tumor cell strains, and human myeloic leukemia cells (from two patients) had high fusion capacities. The capacities of short term tissue culture cells (from monkey, mouse, chicken and cow) were low. Leucocytes (mouse monocytes, polymorph leucocytes and lymphocytes; human polymorph leucocytes and lymphocytes; and rabbit lymphocytes) had no fusion capacity. From these observations, it was concluded that differentiated somatic cells may have no fusion capacity in the presence of HVJ, while malignant cells or undifferentiated cells may have fusion capacities in proportion to their degree of undifferentiation. Cell fusion is a direct reaction between neighboring cell surfaces and the fusion activity sites of the virus. The fusion efficiency of a cell strain depends directly on the structure of the cell surface. Thus, it might be that the structure of the cell surface of undifferentiated cells is different from that of somatic cells.