Department of Microbiology & Immunology, Miller School of Medicine, University of Miami, 1580 NW 10th Ave, Miami, FL, USA.
Vaccine. 2011 Mar 3;29(11):2110-9. doi: 10.1016/j.vaccine.2010.12.131. Epub 2011 Jan 15.
Dendritic cell (DC) therapy is a promising technology for the treatment of HIV infected individuals. HIV-1 Gag- and Nef RNA-loaded DC have previously been shown to induce immune responses ex vivo following coculture with autologous lymphocytes. However, polyfunctionality and memory responses following coculture have not been evaluated. In addition, little is known regarding whether specific HIV-1 proteome components, such as highly conserved regions of the HIV-1, could enhance clinical responses following DC therapy.
To determine the breadth of the immune responses to antigen loaded DC, we analyzed polyfunctional T cell response ex vivo to Gag RNA loaded DC. Blood samples were used to generate monocyte derived DC, which were then matured and cocultured with autologous lymphocytes. We found that cytokine-matured DC loaded with Gag RNA was able to induce Gag-specific IFN-γ and IL-2 responses after a 12-day coculture. We characterized these responses by polyfunctional intracellular cytokine staining and evaluation of T cell memory phenotypes. Central memory CD8+ T cells were induced ex vivo after DC coculture from each of 3 patients, and the effector memory pool was increased by DC coculture from 2 patients. We also observed a decrease in the terminal effector and intermediate CD8+ T cell pool and an increase in the naïve/other population. There was a reduction in terminal effector and intermediate CD4+ T cells, and a corresponding increase in naïve/other CD4+ T cells. Finally, we evaluated conserved regions of Gag as a novel DC therapy immunogen and found that a conserved element (CE) p24 Gag antigen elicited IFN-γ and IL-2 responses comparable to those induced by a full-length Gag antigen.
We showed that RNA-loaded DC therapy induced a polyfunctional T cell response ex vivo, supporting the use of such DC-therapy for HIV infection. However, the central and effector memory phenotypes of T cells did not appear to be enhanced during coculture with Gag RNA-loaded DC. Furthermore, comparable antigen-specific responses were induced in HIV infected individuals using full-length Gag or only conserved elements of the Gag p24 protein. This indicates that immune responses can be focused onto the conserved elements of Gag in the absence of other Gag components.
树突状细胞（DC）疗法是治疗 HIV 感染者的一种很有前途的技术。先前已经证明，负载 HIV-1 Gag 和 Nef RNA 的 DC 在与自体淋巴细胞共培养后，可以在体外诱导免疫反应。然而，共培养后多效性功能和记忆反应尚未得到评估。此外，对于负载 HIV-1 衣壳蛋白（Gag）的 DC 治疗后是否能够增强临床反应，人们对特定的 HIV-1 蛋白组成分（如 HIV-1 的高度保守区域）知之甚少。
为了确定负载抗原的 DC 所引起的免疫反应的广度，我们分析了负载 Gag RNA 的 DC 体外多效性 T 细胞反应。使用血液样本生成单核细胞来源的 DC，然后使其成熟并与自体淋巴细胞共培养。我们发现，经过细胞因子成熟的负载 Gag RNA 的 DC 在 12 天共培养后能够诱导 Gag 特异性 IFN-γ 和 IL-2 反应。我们通过多效性细胞内细胞因子染色和 T 细胞记忆表型评估来对这些反应进行了特征描述。从 3 名患者的 DC 共培养中，体外诱导了中央记忆 CD8+T 细胞，从 2 名患者的 DC 共培养中，效应记忆池增加。我们还观察到终末效应和中间 CD8+T 细胞池减少，幼稚/其他群体增加。终端效应和中间 CD4+T 细胞减少，相应的幼稚/其他 CD4+T 细胞增加。最后，我们评估了 Gag 的保守区域作为一种新的 DC 治疗免疫原，发现保守元件（CE）p24 Gag 抗原引起的 IFN-γ 和 IL-2 反应与全长 Gag 抗原诱导的反应相当。
我们表明，负载 RNA 的 DC 治疗在体外诱导了多效性 T 细胞反应，支持将这种 DC 疗法用于 HIV 感染。然而，在与负载 Gag RNA 的 DC 共培养过程中，T 细胞的中央和效应记忆表型似乎没有增强。此外，在 HIV 感染者中，使用全长 Gag 或 Gag p24 蛋白的仅保守元件也能诱导相当的抗原特异性反应。这表明可以将免疫反应集中在 Gag 的保守元件上，而无需其他 Gag 成分。
