主页 > 医学新闻 >
【PNAS——编译】:HIV-1模型的建立
(http://www.pnas.org/cgi/content/full/102/10/3760)
A mouse model for study of systemic HIV-1 infection, antiviral immune responses, and neuroinvasiveness
Abstract
We created a model of HIV-1 infection of conventional mice for investigation of viral replication, control, and pathogenesis. To target HIV-1 to mice, the coding region of gp120 in HIV-1/NL4-3 was replaced with that of gp80 from ecotropic murine leukemia virus, a retrovirus that infects only rodents. The resulting chimeric virus construct, EcoHIV, productively infected murine lymphocytes, but not human lymphocytes, in culture. Adult, immunocompetent mice were readily susceptible to infection by a single inoculation of EcoHIV as shown by detection of virus in splenic lymphocytes, peritoneal macrophages, and the brain. The virus produced in animals was infectious, as shown by passage in culture, and immunogenic, as shown by induction of antibodies to HIV-1 Gag and Tat. A second chimeric virus based on clade D HIV-1/NDK was also highly infectious in mice; it was detected in both spleen and brain 3 wk after tail vein inoculation, and it induced expression of infection response genes, MCP-1, STAT1, IL-1 , and complement component C3, in brain tissue as determined by quantitative real-time PCR. EcoHIV infection of mice forms a useful model of HIV-1 infection of human beings for convenient and safe investigation of HIV-1 therapy, vaccines, and potentially pathogenesis.
animal model | AIDS | brain | vaccine
HIV-1 naturally infects human beings and can also infect a small number of nonhuman primate species (1). This restriction in host range severely limits the animal models suitable for the study of HIV-1 disease development and control. Mice are attractive candidates for HIV-1 research because of the versatility in inbred and genetically engineered strains and the extensive knowledge of the murine immune system. However, mice are not susceptible to HIV-1 and investigation of HIV-1 replication in mouse cell lines in culture was generally disappointing. Blocks at virus entry (2) and after transfection of viral DNA were shown in early studies in NIH 3T3 cells (3), a murine fibroblast cell line. Consistent with these general defects, Rev and Tat, viral proteins originally described in HIV-1, were found to function poorly in NIH 3T3 cells (4, 5). The latter defect was attributed to the inability of murine cyclin T1 to associate with Tat during the formation of a complex with TAR RNA required for efficient transcription . In contrast to studies in murine cell lines in culture, animals transgenic for the entire HIV-1 genome driven by the viral LTR expressed virus in skin and lymph nodes (7) or in leukocytes , and virus expression could be induced in the animal by physiological stimuli. These studies indicate that primary mouse cells, unlike NIH 3T3 cells, are permissive to late stages of the virus life cycle . Consistent with this interpretation, we and others (9, 10) have shown that bypassing restrictions in virus entry through DNA transfection or through pseudotyping permits efficient HIV-1 expression and the production of infectious progeny virus in rat cell lines or primary rat cells in culture. More recently, we have also demonstrated that murine lymphocytes, macrophages, and astrocytes produced viral RNA, protein, and infectious progeny upon infection by HIV-1/NL4-3 pseudotyped by vesicular stomatitis virus envelope glycoprotein G, and similar findings were reported when HIV-1 pseudotyped with murine leukemia virus (MLV) envelope was used (11, 12).
Because primary mouse cells are permissive to HIV-1 expression (11, 12), the principal difficulty in constructing mouse models of HIV-1 infection is inefficient virus binding and entry into murine cells. Models using mice or rats transgenic for the human receptors for HIV-1, CD4, and either CCR5 or CXCR4 were poorly susceptible to HIV-1 infection (13, 14). We adopted a different strategy based on studies of infection in culture by HIV-1 enveloped by heterologous proteins (11, 12, 15). Rather than endow mice with receptors for HIV-1, we constructed HIV-1 species with receptors for mouse cells. As described here, we converted the host species range of HIV-1 from primate to rodent by replacing the coding region of its surface envelope glycoprotein, gp120, with the envelope-coding region from ecotropic MLV that restricts the replication of the virus to rodents (16). We constructed two such chimeric viruses, EcoHIV on a backbone of clade B NL4-3 (17) and EcoNDK on a backbone of clade D NDK (18). The chimeric virus replicated in murine lymphocytes but not human lymphocytes in culture. EcoHIV and EcoNDK established systemic infection in mice after one inoculation. This experimental infection reproduced several major characteristics of HIV-1 infection of human beings, including virus targeting to lymphocytes and macrophages, induction of antiviral immune responses, neuroinvasiveness, and elevation of expression of inflammatory and antiviral factors in the brain. These findings indicate that EcoHIV and similar chimeric viruses can serve as important tools for investigation of HIV-1 disease and intervention in a versatile and convenient animal host.
阅读本文的人还阅读：
作者:admin@医学,生命科学 2011-05-29 05:14
医学,生命科学网