科學(xué)家發(fā)現(xiàn)，感染2型人類(lèi)免疫缺陷病毒（HIV-2）但是不發(fā)病的人們能針對(duì)一種特定的病毒蛋白質(zhì)產(chǎn)生很強(qiáng)的免疫應(yīng)答,。這項(xiàng)研究可能有助于開(kāi)發(fā)艾滋病疫苗,。
HIV-2與HIV-1不同,，前者很少造成艾滋病發(fā)病，大約80%的HIV-2患者從不表現(xiàn)出臨床癥狀,。
來(lái)自岡比亞共和國(guó),、幾內(nèi)亞比紹共和國(guó)和英國(guó)的科學(xué)家分析了來(lái)自幾內(nèi)亞比紹的一組共64名無(wú)癥狀的HIV-2患者。
他們發(fā)現(xiàn)這些患者的免疫系統(tǒng)——特別是他們的一種免疫細(xì)胞T細(xì)胞——能夠?qū)σ环N名為Gag的病毒蛋白質(zhì)做出顯著的反應(yīng),，這幫助了他們控制病毒的復(fù)制,。Gag也是HIV-1病毒的成分。
人體對(duì)Gag蛋白的反應(yīng)越強(qiáng),，血液中的HIV-2病毒的水平就越低,。那些反應(yīng)最強(qiáng)的患者的血液中檢測(cè)不到病毒。
這項(xiàng)研究發(fā)表在了本月（9月6日）出版的《臨床調(diào)查雜志》上,。
它證明了在HIV-2患者中,，T細(xì)胞的免疫應(yīng)答足夠控制感染。這一發(fā)現(xiàn)很重要,，因?yàn)榭茖W(xué)家在設(shè)計(jì)疫苗的時(shí)候,，必須決定應(yīng)該激活哪種免疫系統(tǒng)（抗體還是T細(xì)胞），用于對(duì)抗HIV,。
該研究論文的第一作者,、英國(guó)醫(yī)學(xué)研究理事會(huì)人類(lèi)免疫組的Aleksandra Leligdowicz告訴本網(wǎng)站說(shuō)：“HIV患者產(chǎn)生針對(duì)Gag蛋白的T細(xì)胞用于控制病毒復(fù)制，知道這一事實(shí)可以開(kāi)發(fā)基于T細(xì)胞的預(yù)防和治療性疫苗,。”
這是科學(xué)家首次研究無(wú)癥狀的HIV-2患者,，這可以讓科學(xué)家分析他們的保護(hù)性的免疫應(yīng)答,。
參與該研究的岡比亞科學(xué)家Assan Jaye告訴本網(wǎng)站說(shuō)，由于HIV-1也擁有Gag基因,，我們?nèi)缃?ldquo;更加了解如何最好地設(shè)計(jì)艾滋病疫苗”,。
一些無(wú)癥狀的HIV-1患者也對(duì)這種蛋白產(chǎn)生了很強(qiáng)的免疫應(yīng)答。
Jaye還說(shuō),，這項(xiàng)研究很重要,，這也是因?yàn)樗C明了特定的免疫應(yīng)答而不是總體免疫應(yīng)答的水平對(duì)于抵抗HIV起了關(guān)鍵作用。
幾內(nèi)亞比紹擁有全世界最高的HIV-2感染率,，全國(guó)最多20%的40歲以上成年人感染了這種病毒,。HIV-2大多見(jiàn)于西非，而且很少導(dǎo)致死亡,。（科學(xué)與發(fā)展網(wǎng)）
原始出處：
Published Online September 6, 2007
J. Clin. Invest. doi:10.1172/JCI32380.
Robust Gag-specific T cell responses characterize viremia control in HIV-2 infection
Aleksandra Leligdowicz1,2, Louis-Marie Yindom1, Clayton Onyango1, Ramu Sarge-Njie1, Abraham Alabi1, Matthew Cotten1, Tim Vincent1,3, Carlos da Costa3, Peter Aaby3, Assan Jaye1, Tao Dong2, Andrew McMichael2, Hilton Whittle1 and Sarah Rowland-Jones1,2
1Medical Research Council Laboratories, Fajara, Republic of The Gambia. 2Weatherall Institute of Molecular Medicine, Medical Research Council Human Immunology Unit, John Radcliffe Hospital, Oxford, United Kingdom. 3Projecto Saude Bandim, Bissau, Republic of Guinea-Bissau.
Address correspondence to: Aleksandra Leligdowicz, Weatherall Institute of Molecular Medicine, MRC Human Immunology Unit, John Radcliffe Hospital, Oxford, OX3 9DS, United Kingdom. Phone: 44-1865-222312; Fax: 44-1865-222502; E-mail: [email protected] .
Received for publication April 11, 2007, and accepted in revised form June 13, 2007.
HIV-2 infection in the majority of infected subjects follows an attenuated disease course that distinguishes it from infection with HIV-1. Antigen-specific T cells are pivotal in the management of chronic viral infections but are not sufficient to control viral replication in HIV-1–positive subjects, and their function in HIV-2 infection is not fully established. In a community-based cohort of HIV-2 long-term nonprogressors in rural Guinea-Bissau, we performed what we believe is the first comprehensive analysis of HIV-2–specific immune responses. We demonstrate that Gag is the most immunogenic protein. The magnitude of the IFN- immune response to the HIV-2 proteome was inversely correlated with HIV-2 viremia, and this relationship was specifically due to the targeting of Gag. Furthermore, patients with undetectable viremia had greater Gag-specific responses compared with patients with high viral replication. The most frequently recognized peptides clustered within a defined region of Gag, and responses to a single peptide in this region were associated with low viral burden. The consistent relationship between Gag-specific immune responses and viremia control suggests that T cell responses are vital in determining the superior outcome of HIV-2 infection. A better understanding of how HIV-2 infection is controlled may identify correlates of effective protective immunity essential for the design of HIV vaccines.
