Activation. To determine if the CD96 expression was changed during HIV-1 infection, we assessed CD96 expression by CD8+ T cells in elite controllers (EC) (mean 961 CD4+ T cells/mm3 and , 50 RNA copies/ml), HIV-1 non-controllers (NC) (mean 536 CD4+ T cells/mm3 and mean 68,049 RNA copies/ml) and healthy controls (HC). Representative histograms and dot plots of CD96 expression in healthy controls (HC), elite controllers (EC) and noncontrollers (NC) are shown in Figure 1A, where CD96 expression was determined based on fluorescence minus one (FMO) control. We found that a high percentage of resting CD8+ T cells expressed CD96 in healthy individuals (Fig. 1B). Unexpectedly, the frequency of CD96-expressing CD8+ T cells was significantly lower in both HIV-1 infected groups (p , 0.001 for both groups) compared to healthy controls (HC) (Fig. 1B). However, the frequency of CD96-expressing CD8+ T cells was significantly higher in the EC group compared to the NC group 22948146 (p , 0.05). Furthermore, the CD96 mean fluorescence intensity (MFI) on CD8+ T cells was significantly lower in the 15481974 NC group (mean MFI = 510) compared to the healthy controls (mean MFI = 690, Fig. 1C). In contrast the mean CD96 MFI in the EC group (mean MFI = 606) was comparable to healthy controls and was significantly higher than that of the NC group (p , 0.01). To determine if the lower frequencies in CD96-expressing CD8+ T cells were a reflection 
of changes in the total T cell composition commonly seen in HIV-1 infected individuals, we also assessed absolute numbers of CD96+ T cells. We found that the number of CD8+ T cells expressing CD96 was similar in both HIV-1 groups and healthy controls suggesting that the total CD8+ T cell subset population was expanded in HIV-1 infected patients, with an increased CD96 negative population (data not shown). In contrast to CD96 expression and a previous report [19] CD226 expression on CD8+ T cells was unchanged in all HIV-1 infected subjects (data not shown). All together these results show that even though CD96 is considered a T cell activation marker, HIV-1 infection, in particular uncontrolled infection, appears to promote downregulation of CD96 expression. Furthermore, despite the close relationship and similar characteristics of CD96 and CD226, they are differentially affected by HIV-1 infection.and TCM CD8+ T cells were significantly lower than in healthy controls, the majority of cells in these subsets maintained CD96 expression. The CD96 MFI in all subsets was comparable between EC and healthy controls (Fig. 1E). In the NC group, the CD96 MFI was ASP015K slightly reduced in the TCM cell subset compared to healthy controls (p , 0.05). HIF-2��-IN-1 Additionally the CD96 MFI in the TEM cell subset was significantly lower in the NC group compared to both healthy controls (p , 0.001) and the EC group (p , 0.01). Since we had observed that the CD96 MFI for the total CD8+ T cell population was higher in the EC group than in the NC group 
(Fig. 1C), this suggests that the difference in CD96 MFI between these groups was predominantly attributed to differential CD96 expression within the TEM population. Collectively, these results also indicate that CD8+ T cell differentiation alone is not sufficient to down-regulate CD96 expression.CD96 is Down-regulated Following Stimulation with LPSChronic immune activation is a well-established characteristic of HIV-1 infection and has been associated with factors such as inflammatory responses, the presence of LPS in plasma as.Activation. To determine if the CD96 expression was changed during HIV-1 infection, we assessed CD96 expression by CD8+ T cells in elite controllers (EC) (mean 961 CD4+ T cells/mm3 and , 50 RNA copies/ml), HIV-1 non-controllers (NC) (mean 536 CD4+ T cells/mm3 and mean 68,049 RNA copies/ml) and healthy controls (HC). Representative histograms and dot plots of CD96 expression in healthy controls (HC), elite controllers (EC) and noncontrollers (NC) are shown in Figure 1A, where CD96 expression was determined based on fluorescence minus one (FMO) control. We found that a high percentage of resting CD8+ T cells expressed CD96 in healthy individuals (Fig. 1B). Unexpectedly, the frequency of CD96-expressing CD8+ T cells was significantly lower in both HIV-1 infected groups (p , 0.001 for both groups) compared to healthy controls (HC) (Fig. 1B). However, the frequency of CD96-expressing CD8+ T cells was significantly higher in the EC group compared to the NC group 22948146 (p , 0.05). Furthermore, the CD96 mean fluorescence intensity (MFI) on CD8+ T cells was significantly lower in the 15481974 NC group (mean MFI = 510) compared to the healthy controls (mean MFI = 690, Fig. 1C). In contrast the mean CD96 MFI in the EC group (mean MFI = 606) was comparable to healthy controls and was significantly higher than that of the NC group (p , 0.01). To determine if the lower frequencies in CD96-expressing CD8+ T cells were a reflection of changes in the total T cell composition commonly seen in HIV-1 infected individuals, we also assessed absolute numbers of CD96+ T cells. We found that the number of CD8+ T cells expressing CD96 was similar in both HIV-1 groups and healthy controls suggesting that the total CD8+ T cell subset population was expanded in HIV-1 infected patients, with an increased CD96 negative population (data not shown). In contrast to CD96 expression and a previous report [19] CD226 expression on CD8+ T cells was unchanged in all HIV-1 infected subjects (data not shown). All together these results show that even though CD96 is considered a T cell activation marker, HIV-1 infection, in particular uncontrolled infection, appears to promote downregulation of CD96 expression. Furthermore, despite the close relationship and similar characteristics of CD96 and CD226, they are differentially affected by HIV-1 infection.and TCM CD8+ T cells were significantly lower than in healthy controls, the majority of cells in these subsets maintained CD96 expression. The CD96 MFI in all subsets was comparable between EC and healthy controls (Fig. 1E). In the NC group, the CD96 MFI was slightly reduced in the TCM cell subset compared to healthy controls (p , 0.05). Additionally the CD96 MFI in the TEM cell subset was significantly lower in the NC group compared to both healthy controls (p , 0.001) and the EC group (p , 0.01). Since we had observed that the CD96 MFI for the total CD8+ T cell population was higher in the EC group than in the NC group (Fig. 1C), this suggests that the difference in CD96 MFI between these groups was predominantly attributed to differential CD96 expression within the TEM population. Collectively, these results also indicate that CD8+ T cell differentiation alone is not sufficient to down-regulate CD96 expression.CD96 is Down-regulated Following Stimulation with LPSChronic immune activation is a well-established characteristic of HIV-1 infection and has been associated with factors such as inflammatory responses, the presence of LPS in plasma as.
