REGULATION OF SUSCEPTIBILITY AND CELL-SURFACE RECEPTOR FOR THE B-LYMPHOTROPIC PAPOVAVIRUS BY N-GLYCOSYLATION

The host range of the B-lymphotropic papovavirus (LPV) in cultured hum an cells is limited to a few B-lymphoma-derived cell lines. The consti tutively expressed cell surface receptor for the virus is a major dete rminant restricting the LPV host range (G. Haun, O. T. Keppler, C. T. Beck, M. Herrmann, H. Zentgraf, and M. Pawlita, J. Virol. 67:7482-7492 , 1993). Here we show that human B-lymphoma cells with low-level susce ptibility are rendered highly susceptible to LPV infection by pretreat ment with the N glycosylation inhibitor tunicamycin but remain nonsusc eptible to infection by the related polyomavirus simian virus 40. Amon g the selective N glycosylation processing inhibitors, deoxymannojirim ycin, but not deoxynojirimycin, swainsonine, or castanospermine, could mimic the effect of tunicamycin. Tunicamycin treatment also induced a drastic enhancement of the cells' LPV-binding capacity, indicating th at the induction of LPV susceptibility might be mediated by an increas e in the number of functional cell surface receptors and/or by increas ed receptor affinity. Sialidase sensitivity of the tunicamycin-induced LPV receptor showed that oligosaccharides carrying terminal sialic ac ids are necessary for binding and are likely to be O linked. The const itutive LPV receptor is also sialic acid dependent, which points to a possible identity with the sialic acid-dependent tunicamycin-induced L PV receptor. We conclude that removal or modification of certain N-lin ked oligosaccharides in human B-lymphoma cells can enhance expression or functional activity of the sialylated LPV receptor.