科學家發(fā)現,，感染2型人類免疫缺陷病毒（HIV-2）但是不發(fā)病的人們能針對一種特定的病毒蛋白質產生很強的免疫應答。這項研究可能有助于開發(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患者從不表現出臨床癥狀,。
來自岡比亞共和國,、幾內亞比紹共和國和英國的科學家分析了來自幾內亞比紹的一組共64名無癥狀的HIV-2患者。
他們發(fā)現這些患者的免疫系統(tǒng)——特別是他們的一種免疫細胞T細胞——能夠對一種名為Gag的病毒蛋白質做出顯著的反應,，這幫助了他們控制病毒的復制,。Gag也是HIV-1病毒的成分,。
人體對Gag蛋白的反應越強，血液中的HIV-2病毒的水平就越低,。那些反應最強的患者的血液中檢測不到病毒,。
這項研究發(fā)表在了本月（9月6日）出版的《臨床調查雜志》上。
它證明了在HIV-2患者中,，T細胞的免疫應答足夠控制感染,。這一發(fā)現很重要，因為科學家在設計疫苗的時候,，必須決定應該激活哪種免疫系統(tǒng)（抗體還是T細胞）,，用于對抗HIV。
該研究論文的第一作者,、英國醫(yī)學研究理事會人類免疫組的Aleksandra Leligdowicz告訴本網站說：“HIV患者產生針對Gag蛋白的T細胞用于控制病毒復制,，知道這一事實可以開發(fā)基于T細胞的預防和治療性疫苗。”
這是科學家首次研究無癥狀的HIV-2患者,，這可以讓科學家分析他們的保護性的免疫應答,。
參與該研究的岡比亞科學家Assan Jaye告訴本網站說，由于HIV-1也擁有Gag基因,，我們如今“更加了解如何最好地設計艾滋病疫苗”,。
一些無癥狀的HIV-1患者也對這種蛋白產生了很強的免疫應答。
Jaye還說,，這項研究很重要,，這也是因為它證明了特定的免疫應答而不是總體免疫應答的水平對于抵抗HIV起了關鍵作用。
幾內亞比紹擁有全世界最高的HIV-2感染率,，全國最多20%的40歲以上成年人感染了這種病毒,。HIV-2大多見于西非，而且很少導致死亡,。（科學與發(fā)展網）
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.
