Analysis of VSV pseudotype virus infection mediated by rubella virus envelope proteins

Sakata, Masafumi; Tani, Hideki; Anraku, Masaki; Kataoka, Michiyo; Nagata, Noriyo; Seki, Fumio; Tahara, Maino; Otsuki, Noriyuki; Okamoto, Kiyoko; Takeda, Makoto; Mori, Yoshio

Using the VSV pseudotype system, we have shown that human non-immune cell lines are generally susceptible, while most immune cell lines are much less susceptible to RV than non-immune cells. Therefore, inefficient infection of immune cell lines with the authentic RV is explainable in part by the poor susceptibility of these cell lines to RV. However, previous studies have demonstrated that immune cells can become infected with RV 41-43, 45, 46 . RV replicates in peripheral blood mononuclear cells (PBMCs), of which macrophages are the main target by RV 42 . Consistent with these observations, RV is isolatable from the PBMCs of patients naturally infected with RV 46 . Unstimulated lymphocytes poorly support RV infection 42 , but are able to support RV infection upon stimulation by mitogen [41] [42] [43] . Additionally, a previous study showed that Raji and Cess human B-cell lines and the U937 monocyte line all supported RV infection 45 . Our data do not necessarily contest these previous observations, because a basal level of RV infection was observed in all the immune cell lines, although the efficiency was very low. In addition, our data further demonstrated that the infection of immune cell lines was increased to a certain level by stimulation of the cells. The key point about our data is that the entry efficiency of RV was generally high in non-immune cell lines but not in immune cell lines. These observations are important in terms of understanding more about the pathology of RV.