Growth of rotaviruses in continuous human and monkey cell lines that vary in their expression of integrins

Rotavirus replication occurs in vivo in intestinal epithelial cells. Cell l ines fully permissive to rotavirus include kidney epithelial (MA104), colon ic (Caco-2) and hepatic (HepG2) types. Previously, it has been shown that c ellular integrins alpha 2 beta 1, alpha 4 beta 1 and alpha X beta 2 are inv olved in rotavirus cell entry. As receptor usage is a major determinant of virus tropism, the levels of cell surface expression of these integrins hav e now been investigated by flow cytometry on cell lines of human (Caco-2, H epG2, RD, K562) and monkey (MA104, COS-7) origin in relation to cellular su sceptibility to infection with monkey and human rotaviruses. Cells supporti ng any replication of human rotaviruses (RD, HepG2, Caco-2, COS-7 and MA104 ) expressed alpha 2 beta 1 and (when tested) alpha X beta 2, whereas the no n-permissive K562 cells did not express alpha 2 beta 1, alpha 4 beta 1 or a lpha X beta 2, Only RD cells expressed alpha 4 beta 1. Although SA11 grew t o higher titres in RD, HepG2, Caco-2, COS-7 and MA104 cells, this virus sti ll replicated at a low level in K562 cells. In all cell lines tested, SA11 replicated to higher titres than did human strains, consistent with the abi lity of SA11 to use sialic acids as alternative receptors, Levels of cell s urface alpha 2 integrin correlated with levels of rotavirus growth. The alp ha 2 integrin relative linear median fluorescence intensity on K562, RD, CO S-7, MA104 and Caco-2 cells correlated linearly with the titre of SA11 prod uced in these cells at 20 h after infection at a multiplicity of 0.1, and t he data best fitted a sigmoidal dose-response curve (r(2) = 1.00, P = 0.005 ). Thus, growth of rotaviruses in these cell lines correlates with their su rface expression of alpha 2 beta 1 integrin and is consistent with their ex pression of alpha X beta 2 and alpha 4 beta 1 integrins.