Hemagglutination by human rotavirus strains

Abstract

Human rotavirus isolates, KUN , MO, and Wa strains were found to agglutinate erythrocytes of the day-old chicken and adult goose, optimally at pH 6.6. Only those fractions containing double-shelled rotavirus particles isolated by isopycnic centrifugation in cesium chloride had hemagglutinating activity. Trypsin treatment decreased the hemagglutination titer of human rotavirus strains and conversely increased their infectivity. Hemagglutination inhibition tests with antisera against type-specific antigens demonstrable by neutralization showed no type specificity.

Evidence for endocytosis-independent infection by human rotavirus

“…The virus supernatants were stored at -80 °C until use. The virus stock titers were 5 x 105 fluorescent cell forming units (fefu) per ml [4] with HP~V and 1 × t0 s TCIDs0 per ml with VSV, respectively.…”

“…The KUN strain of HRV (serotype 2, subgroup 1) [7] and the Indiana strain of VSV were used. Infectious HRV was grown in MEM without serum and containing 0.5 gg/ml of trypsin (Sigma type V-S) for 24 hours [4], VSV was grown in MEM without serum for 24 hours. The cultures were freeze-thawed two times and cell debris was removed by low-speed centrifugation.…”

Effect of trypsin and chymotrypsin on polypeptides of human rotavirus KUN strain

“…We have also shown biological effects of trypsin on human rotaviruses (Kitaoka et al 1984;Kitaoka et al 1986 b). In this context, it is of interest to note that trypsin-enhanced plaque formation and growth restriction of the fastidious viruses in tissue culture have been shown to be a function of the 4th gene segment by genetic analysis of cultivable reassortants between a cultivable bovine rotavirus and noncultivable human rotaviruses (Kalica et al 1983).…”

“…Our previous studies revealed that human rotavirus isolates including the KUN strain are activated in infectivity by trypsin treatment, while their hemagglutination activity is decreased (Kitaoka et al 1984; Kitaoka et al 1986 b). It has also been demonstrated that the monoclonal antibodies against HA of the KUN strain react only with Vp4 and its smaller trypsin cleavage products P30 and P24 (Kitaoka et al 1986 a).…”

“…In our studies on the mechanisms by which trypsin enhanced the infectivity of human rotavirus, it was confirmed that the primary effect of trypsin was on the virus, making noninfectious rotavirus particles infectious and permitting multiple cycles of replication in cell culture (Kitaoka et al 1986 b). In addition, it has been demonstrated that while human rotavirus grown in the absence of trypsin has hemagglutination activity, trypsin treatment decreases this capacity, resulting in an enhancement of the infectivity of human rotavirus (Kitaoka et al 1984). In view of the interrelation between infectivity an hemagglutination in human rotavirus, and trypsin treatment, we have analysed in this study the molecular modification by trypsin of the viral polypeptides.…”