ADHESIVE FUNCTION OF NEWCASTLE-DISEASE VIRUS HEMAGGLUTININ IN TUMOR-HOST INTERACTION

Infection of metastatic lymphoma cells (ESbL) by a low dose of a non-l ytic strain of Newcastle disease virus (NDV) leads to viral replicatio n followed by strong cell surface expression of viral antigens, especi ally hemagglutinin neuraminidase (HN). The expressed HN was functional and facilitated cell-cell interactions and cell attachment. This was shown for NDV infected tumor cells, lymphocytes, fibroblasts and endot helial cells. The interactions could be strongly inhibited by antibodi es against the viral HN protein. Increased binding was also seen with HN c-DNA transfectants expressing the HN as the only viral protein. Vi ral infection did not influence proliferation and lysability of the in fected tumor cells. Following intravenous injection of tumor cells, th e number of hepatic metastases was significantly reduced when the cell s had been pre-infected with NDV. This reduction of metastases correla ted with an increased survival time of the animals. As potential mecha nisms of these NDV effects we propose augmentation of cell-eel interac tions and immune functions and reduction of invasive capacity of NDV i nfected, as compared to non-infected tumor cells.