title: Lack of the trans-receptor mechanism of HIV-1 infection: CD4- and coreceptor-independent incorporation of HIV-1-resistant cells into syncytia induced by HIV-1.
abstract: Human immunodeficiency virus type 1 (HIV-1) infects cells through an interaction of HIV-1 envelope protein with CD4 and an appropriate coreceptor on target cells. This interaction often leads to cell fusion, and formation of syncytia. HIV-1-resistant cells expressing either CD4 or a coreceptor are often surrounding HIV-1-susceptible cells, expressing both CD4 and a compatible coreceptor, in vivo. It is therefore worthwhile to investigate whether these HIV-1-resistant cells could cooperate in HIV-1 infection or cell fusion leading to their incorporation into syncytia. When CD4-positive, coreceptor-negative cells were co-cultured with CD4-negative, coreceptor-positive cells and exposed to HIV-1, HIV-1 infection was not established, indicating that CD4 and the coreceptor expressed on different cell surfaces could not cooperate in HIV-1 entry. However, when HIV-1-resistant cells expressing CD4 or a coreceptor or lacking both were mixed with HIV-1-susceptible cells and inoculated with HIV-1, all these HIV-1-resistant cells were similarly incorporated into syncytia induced by HIV-1, indicating a CD4- and coreceptor-independent incorporation of HIV-1-resistant cells into syncytia. This incorporation was impaired by the transfection of these cells with siRNAs for adhesion molecules. Our study demonstrates that HIV-1-resistant cells can be incorporated into syncytia induced by HIV-1 and this incorporation may partially be mediated through adhesion molecules.
authors.affiliation: Department of Virology and Preventive Medicine, Gunma University Graduate School of Medicine, Showa-machi, Maebashi, Gunma 371-8511, Japan.
authors.forename: Sheikh Ariful
authors.initials: SA
authors.lastname: Hoque
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ohtsuki
authors.forename: Masashi
authors.initials: M
authors.lastname: Tatsumi
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Shimizu
authors.forename: Salequl
authors.initials: S
authors.lastname: Islam
authors.forename: Atsushi
authors.initials: A
authors.lastname: Jinno-Oue
authors.forename: Hiroo
authors.initials: H
authors.lastname: Hoshino
mesh_terms: D000818:Animals; D015704:CD4 Antigens / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D020868:Gene Silencing; D015726:Giant Cells / Q000378:metabolism* / Q000821:virology*; D015497:HIV-1 / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D051379:Mice; D034741:RNA, Small Interfering; D019713:Receptors, CCR5 / Q000378:metabolism; D015728:Receptors, HIV / Q000378:metabolism*; D013194:Staining and Labeling
chemical_list: D015704:CD4 Antigens; D015815:Cell Adhesion Molecules; D034741:RNA, Small Interfering; D019713:Receptors, CCR5; D015728:Receptors, HIV