pone-0042776-g003: Phenotypic analysis of human CD8+ T cells in HIV-1-infected hNOK/B51Tg and hNOK mice as well as in uninfected ones.hNOK/B51Tg and hNOK mice were infected or not with HIV-1 at 14 weeks after the transplantation of CD34+ HSCs. Then human CD8+ T cells among PBMCs from HIV-1-infected and uninfected hNOK/B51Tg mice as well as HIV-1-infected and uninfected hNOK mice were analyzed for their expression of the following cell-surface markers: CD8, CD27, CD28, CD45RA, and CCR7. (A) Representative results of 5-color flow cytometric analysis of the human CD8+ T cell population in PBMCs from HIV-1-infected hNOK/B51Tg and HIV-1-infected hNOK mice at 6 weeks post-infection. (B) Same analysis as in “A” for uninfected hNOK/B51Tg and uninfected hNOK mice at 20 weeks after the transplantation of CD34+ HSCs. (C) Summarized results on the frequency of naive (CD27highCD28+CD45RA+CCR7+), central memory (CM: CD27+CD28+CD45RA−CCR7+), early effector memory (EEM: CD27+CD28+CD45RA−CCR7−), and late effector memory (LEM: CD27lowCD28−CD45RA+/−CCR7−) plus effector (CD27−CD28−CD45RA+/−CCR7−) subsets of human CD8+ T cells among PBMCs from HIV-1-infected hNOK/B51Tg mice at 0, 2, 4, and 6 weeks post-infection (n = 11, black circles) and from uninfected ones at 14, 16, 18, and 20 weeks after the transplantation of CD34+ HSCs (n = 8, white circles) as well as those from HIV-1-infected hNOK mice (n = 8, black triangles) and from uninfected ones (n = 8, white triangles). Each symbol represents an individual mouse; and the mean value is shown as a horizontal solid line. Asterisks indicate statistically significant differences (*p<0.05, HIV-1-infected mice vs. uninfected ones).

Mentions: Human peripheral CD8+ T cells are also classified into 5 major populations by the same 4 cell-surface markers, i.e., CD27highCD28+CD45RA+CCR7+ (naive subset), CD27+CD28+CD45RA−CCR7+ (central memory subset: CM), CD27+CD28+CD45RA−CCR7− (early effector memory subset: EEM), CD27lowCD28−CD45RA+/−CCR7− (late effector memory subset: LEM), and CD27−CD28−CD45RA+/−CCR7− (effector subset) [32], [33]. We previously showed that human CD8+ T cells can not differentiate into effector cells in hNOK mice stimulated with allo-antigen, because human CD8+ T cells are not educated by HLA in the mouse thymus [16]. To investigate the differentiation of human CD8+ T cells in hNOK/B51Tg and hNOK mice, we analyzed the phenotype of these cells among PBMCs from these mice. Representative data from uninfected hNOK/B51Tg and hNOK mice are shown in Figure 3B; and summaries of the results from 8 hNOK/B51Tg and 8 hNOK uninfected mice, in Figure 3C. Without stimulation there were no differences in the frequency of CD27lowCD28−CD45RA+/−CCR7− late effector memory and CD27−CD28−CD45RA+/−CCR7− effector subsets among human CD8+ T cells between hNOK/B51Tg and hNOK mice. To clarify whether the differentiation of human CD8+ T cells was induced in hNOK/B51Tg and hNOK mice after an HIV-1 infection, we further analyzed the phenotype of human CD8+ T cells in PBMCs from the mice every 2 weeks post-infection. Representative results from HIV-1-infected hNOK/B51Tg and HIV-1-infected hNOK mice at 6 weeks post-infection are shown in Figure 3A; and summaries of the results from 11 HIV-1-infected hNOK/B51Tg and 8 HIV-1-infected hNOK mice, in Figure 3C. The frequency of LEM and effector subsets among human CD8+ T cells from HIV-1-infected hNOK/B51Tg mice at 4 and 6 weeks post-infection was significantly higher than that for the uninfected ones. On the other hand, a very low frequency of these subsets was detected in PBMCs from HIV-1-infected hNOK mice. These results suggest that human CD8+ T cells effectively differentiated into effector cells in the HIV-1-infected hNOK/B51Tg mice but not in the HIV-1-infected hNOK mice.