Reovirus binds to multiple plasma membrane proteins of mouse L fibroblasts

Plasma membranes from mouse L fibroblasts were isolated and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Resolved proteins were electroblotted to nitrocellulose paper and probed with ¹²⁵I-labeled type 3 (T3) reovirus. Multiple protein bands with molecular weights ranging from 26 to 200 kDa were consistently recognized by the virus. Such binding was specific since it was blocked in the presence of unlabeled virus. That these proteins were exposed on the cell surface was confirmed by their susceptibility to sulfo-NHS-LC-biotin labeling of intact cells prior to membrane purification. Blots probed with wheat germ agglutinin (WGA)-gold showed a similar pattern of protein bands. These findings are consistent with the ability of WGA to block reovirus binding to L cells, and with our recent demonstration that the α-anomeric form of sialic acid is the minimal receptor determinant recognized by reovirus (R. W. Paul, A. H. C. Choi, and P. W. K. Lee, Virology 172, 382-385,1989). Both type 1 and type 3 reoviruses were found to recognize the same set of multiple proteins on the blot, which is again consistent with the previous observation that the two serotypes compete with each other for binding to intact L cells (P. W. K. Lee, E. C. Hayes, and W. K. Joklik, Virology 108, 156-163, 1981).