Hsu E C, Sarangi F, Iorio C, Sidhu M S, Udem S A, Dillehay D L, Xu W, Rota P A, Bellini W J, Richardson C D
Department of Medical Biophysics, University of Toronto, Ontario, Canada.
J Virol. 1998 Apr;72(4):2905-16. doi: 10.1128/JVI.72.4.2905-2916.1998.
This paper provides evidence for a measles virus receptor other than CD46 on transformed marmoset and human B cells. We first showed that most tissues of marmosets are missing the SCR1 domain of CD46, which is essential for the binding of Edmonston measles virus, a laboratory strain that has been propagated in Vero monkey kidney cells. In spite of this deletion, the common marmoset was shown to be susceptible to infections by wild-type isolates of measles virus, although they did not support Edmonston measles virus production. As one would expect from these results, measles virus could not be propagated in owl monkey or marmoset kidney cell lines, but surprisingly, both a wild-type isolate (Montefiore 89) and the Edmonston laboratory strain of measles virus grew efficiently in B95-8 marmoset B cells. In addition, antibodies directed against CD46 had no effect on wild-type infections of marmoset B cells and only partially inhibited the replication of the Edmonston laboratory strain in the same cells. A direct binding assay with insect cells expressing the hemagglutinin (H) proteins of either the Edmonston or Montefiore 89 measles virus strains was used to probe the receptors on these B cells. Insect cells expressing Edmonston H but not the wild-type H bound to rodent cells with CD46 on their surface. On the other hand, both the Montefiore 89 H and Edmonston H proteins adhered to marmoset and human B cells. Most wild-type H proteins have asparagine residues at position 481 and can be converted to a CD46-binding phenotype by replacement of the residue with tyrosine. Similarly, the Edmonston H protein did not bind CD46 when its Tyr481 was converted to asparagine. However, this mutation did not affect the ability of Edmonston H to bind marmoset and human B cells. The preceding results provide evidence, through the use of a direct binding assay, that a second receptor for measles virus is present on primate B cells.
本文提供了证据，表明在转化的狨猴和人B细胞上存在一种不同于CD46的麻疹病毒受体。我们首先发现，狨猴的大多数组织缺失了CD46的SCR1结构域，而该结构域对于Edmonston麻疹病毒（一种在Vero猴肾细胞中传代的实验室毒株）的结合至关重要。尽管存在这种缺失，但普通狨猴仍被证明对麻疹病毒野生型分离株感染敏感，不过它们不支持Edmonston麻疹病毒的产生。从这些结果可以预料到，麻疹病毒无法在夜猴或狨猴肾细胞系中传代，但令人惊讶的是，一种野生型分离株（Montefiore 89）和麻疹病毒的Edmonston实验室毒株都能在B95 - 8狨猴B细胞中高效生长。此外，针对CD46的抗体对狨猴B细胞的野生型感染没有影响，并且仅部分抑制了Edmonston实验室毒株在相同细胞中的复制。使用表达Edmonston或Montefiore 89麻疹病毒株血凝素（H）蛋白的昆虫细胞进行直接结合试验，以探测这些B细胞上的受体。表达Edmonston H但不表达野生型H的昆虫细胞与表面带有CD46的啮齿动物细胞结合。另一方面，Montefiore 89 H和Edmonston H蛋白都能黏附到狨猴和人B细胞上。大多数野生型H蛋白在第481位有天冬酰胺残基，通过将该残基替换为酪氨酸可转变为与CD46结合的表型。同样，当Edmonston H蛋白的Tyr481转变为天冬酰胺时，它不再结合CD46。然而，这种突变并不影响Edmonston H蛋白结合狨猴和人B细胞的能力。上述结果通过直接结合试验提供了证据，表明灵长类B细胞上存在麻疹病毒的第二种受体。
