Identification of a factor produced by anti-HIV CD4+ T cells induced by dendritic cell-based immunization in the hu-PBL-SCID mice

我们之前报道过，用人外周血单核细胞（PBMC） （hu-PBL-SCID小鼠）和灭活的人类免疫缺陷病毒1型脉冲（HIV-1）自体树突状细胞（HIV-DC）免疫重组的严重联合免疫缺陷（SCID）小鼠，可诱导HIV-1反应性CD4^+ T细胞在体外产生一种尚未定义的新型可溶性因子，具有抗CCR5热带（R5） HIV-1感染的抗病毒特性。这些发现引导我们进行研究，旨在鉴定体内合成这种因子的细胞谱系，并确定HIV-1蛋白的表位，这些表位具有诱导这种抗病毒因子的特异性。我们的研究结果表明，这种特性是CD4^+而不是CD8^+ T细胞的功能。因此，从hiv - dc免疫的hu-PBL-SCID小鼠中恢复人类CD4^+ T细胞，并在体外与自体贴壁PBMC共培养2天，作为抗原呈递细胞（APC），在含il -2的培养基中被灭活的HIV-1脉冲，以扩增HIV-1反应性CD4^+ T细胞。然后将这些再刺激的CD4^+ T细胞等量与先前用10 mg/ml HIV-1肽组脉冲的类似APC共培养2天，并检测其培养上清的R5 HIV-1抑制因子和IFN-g的产生。本文提供的数据表明，HIV-1引发的CD4^+ T细胞产生R5抑制因子，以响应多种HIV-1 gag、env、pol、nef或vif肽，这取决于CD4^+ T细胞的供体。在一些病例中观察到同时产生人干扰素(IFN)-g。这些结果表明，HIV-1初始供者PBMC中的人CD4^+ T细胞具有多种HIV-1表位特异性CD4^+ T细胞前体，在以dc为基础的全灭活HIV-1疫苗接种后能够产生R5 HIV-1抑制因子。

We have previously reported that immunization of the severe combined immunodifficiency (SCID) mice reconstituted with human peripheral blood mononuclear cells (PBMC) (hu-PBL-SCID mice) with inactivated human immunodeficiency virus type-1-pulsed (HIV-1)-autologous dendritic cells (HIV-DC) elicits HIV-1-reactive CD4^+ T cells that produce an as yet to be defined novel soluble factor in vitro with anti-viral properties against CCR5 tropic-(R5) HIV-1 infection. These findings led us to perform studies designed to identify the lineage of the cell that synthesizes such a factor in vivo and define the epitopes of HIV-1 protein that have specificity for the induction of such anti-viral factor. Results of our studies show that this property is a function of CD4^+ but not CD8^+ T cells. Human CD4^+ T cells were thus recovered from the HIV-DC-immunized hu-PBL-SCID mice and were re-stimulated in vitro by co-culture for 2 days with autologous adherent PBMC as antigen presenting cells (APC) previously pulsed with inactivated HIV-1 in IL-2-containing medium to expand HIV-1-reactive CD4^+ T cells. Aliquots of these re-stimulated CD4^+ T cells were then co-cultured with similar APC's that were previously pulsed with 10 mg/ml of a panel of HIV-1 peptides for an additional 2 days, and their culture supernatants were examined for the production of both the R5 HIV-1 suppression factor and IFN-g. The data presented herein show that the HIV-1 primed CD4^+ T cells produced the R5 suppression factor in response to a wide variety of HIV-1 gag, env, pol, nef or vif peptides, depending on the donor of the CD4^+ T cells. Simultaneous production of human interferon (IFN)-g was observed in some cases. These results indicate that human CD4^+ T cells in PBMC of HIV-1 naive donors have a wide variety of HIV-1 epitope-specific CD4^+ T cell precursors that are capable of producing the R5 HIV-1 suppression factor upon DC-based vaccination with whole inactivated HIV-1.