HUMAN-IMMUNODEFICIENCY-VIRUS ENVELOPE GLYCOPROTEIN CD4-MEDIATED FUSION OF NONPRIMATE CELLS WITH HUMAN-CELLS
HUMAN-IMMUNODEFICIENCY-VIRUS ENVELOPE GLYCOPROTEIN CD4-MEDIATED FUSION OF NONPRIMATE CELLS WITH HUMAN-CELLS
复制标题
DOI：
10.1128/jvi.64.5.2149-2156.1990
复制
发表时间：
1990-05-01
影响因子：
5.4
通讯作者：
MOSS, B
中科院分区：
文献类型：
--
作者：
ASHORN, PA;BERGER, EA;MOSS, B
人类免疫缺陷病毒（HIV）通过与表面CD4分子结合并直接与细胞膜融合来感染人类细胞。尽管表达人类 CD4 的小鼠细胞与 HIV 结合，但它们不会被感染，这显然是因为膜融合受阻。为了研究这个问题，我们构建了一种重组痘苗病毒，它可以感染哺乳动物细胞并促进全长 CD4 的瞬时表达。这种病毒与另一种编码具有生物活性的HIV包膜糖蛋白gp160的牛痘重组体一起，使我们能够在没有其他HIV蛋白的情况下研究多种人类和非人类细胞中CD4/gp160介导的细胞-细胞融合。通过使用表达 CD4 和 gp160 的单一细胞类型的合胞体形成测定，我们证明了人类淋巴和非淋巴细胞中存在膜融合，但在来自非洲绿猴、狒狒、兔子、仓鼠、大鼠或小鼠的 23 种测试的非人类细胞类型中没有发现膜融合。然而，在一种表达 CD4 的细胞类型和另一种表达 gp160 的细胞类型的混合实验中，所有这些非人类细胞在与人类细胞混合时都可以形成 CD4/gp160 介导的合胞体；在 23 例中的 20 例中，仅当 CD4 分子在人类细胞上表达时才会发生膜融合，而在其他 3 例中，CD4 可以在任一融合伴侣上表达。有趣的是，在一种小鼠细胞系中，CD4依赖性合胞体在没有人类伴侣的情况下形成，但前提是使用了C端截短形式的HIV包膜糖蛋白。我们的结果表明，非人类细胞本质上能够进行 CD4/gp160 介导的膜融合，但这种融合通常因非人类细胞膜中缺乏辅助因子或存在抑制因子而被阻止。
Human immunodeficiency virus (HIV) infects human cells by binding to surface CD4 molecules and directly fusing with the cell membrane. Although mouse cells expressing human CD4 bind HIV, they do not become infected, apparently because of a block in membrane fusion. To study this problem, we constructed a recombinant vaccinia virus that can infect and promote transient expression of full-length CD4 in mammalian cells. This virus, together with another vaccinia recombinant encoding biologically active HIV envelope glycoprotein gp160, allowed us to study CD4/gp160-mediated cell-cell fusion in a wide variety of human and nonhuman cells in the absence of other HIV proteins. By using syncytium formation assays in which a single cell type expressed both CD4 and gp160, we demonstrated membrane fusion in lymphoid and nonlymphoid human cells but not in any of the 23 tested nonhuman cell types, derived from African green monkey, baboon, rabbit, hamster, rat, or mouse. However, in mixing experiments with one cell type expressing CD4 and the other cell type expressing gp160, all of these nonhuman cells could form CD4/gp160-mediated syncytia when mixed with human cells; in 20 of 23 cases, membrane fusion occurred only if the CD4 molecule was expressed on the human cells whereas in the other three cases, CD4 could be expressed on either one of the fusing partners. Interestingly, in one mouse cell line, CD4-dependent syncytia formed without a human partner, but only if a C-terminally truncated form of the HIV envelope glycoprotein was employed. Our results indicate that nonhuman cells are intrinsically capable of undergoing CD4/gp160-mediated membrane fusion, but this fusion is usually prevented by the lack of helper or the presence of inhibitory factors in the nonhuman cell membranes.