The involvement of different cell membrane components in the receptor structures for SA-11 rotavirus was investigated. As experimental model, the human enterocyte-like HT-29 cell line, was used because of its closer resemblance to the in vivo viral cellular target as compared to other in vitro systems. Rotavirus was incubated with whole membranes or their separated protein and lipid fractions before infection. Either isolated cell membranes or lipid components were capable of binding to the virus and to prevent infection, whereas proteins did not show any inhibitory activity. Among lipids, the glycolipid fraction was shown to impede rotaviral antigen synthesis with a dose-dependent relationship, whereas phospholipids failed to prevent viral infection. To confirm these findings, membranes and target cells were subjected to different enzymatic treatments prior to infection. In addition, HT-29 cells were also incubated with different lectins before infection. The blocking activity of membranes was inhibited by treatment with ceramide glycanase, neuraminidase, and beta-galactosidase but not by treatment with proteases or heat (100°C). Viral infection was prevented by preincubation of target cells with lectins specific for sialic acid and galactose or with ceramide glycanase, neuraminidase, and beta-galactosidase, whereas protease treatments were not active. The results of these experimental procedures indicate that glycolipids containing specific carbohydrate moieties, such as sialic acid and galactose, contribute to the SA-11 rotavirus receptor structure on HT-29 cells.
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