TGF-β and IL-10 Production by HIV-Specific CD8+ T Cells Is Regulated by CTLA-4 Signaling on CD4+ T Cells

Immune dysregulation in HIV-1 infection is associated with increased expression of inhibitory molecules such as CTLA-4, TGF-β, and IL-10. In this study we examined one potential mechanism for regulating TGF-β and IL-10 expression by HIV-specific suppressor CD8+ T cells. No overlap between TGF-β, IL-10, and IFN-γ cytokine production by HIV-specific CD8+ T cells was observed. TGF-β positive and IL-10 positive cells were FOXP3 negative, CD25 negative, and displayed a heterogeneous surface expression of CD127. TGF-β and IL-10 positive CD8+ T cells did not express CTLA-4. Nevertheless, CTLA-4 blockade resulted in a significant decrease in HIV-specific TGF-β positive and IL-10 positive CD8+ T cell responses, and a concomitant increase in HIV-specific IFN-γ positive CD8+ T cell responses. Depletion of CD4+ T cells abrogated the impact of CTLA-4 on HIV-specific TGF-β positive and IL-10 positive CD8+ T cells. Our study suggests that CTLA-4 Signaling on CD4+ T cells regulates the inhibitory functions of the HIV-specific suppressor CD8+ T cells

HIV-Specific TGF-β-Positive CD4+ T Cells Do Not Express Regulatory Surface Markers and Are Regulated by CTLA-4

CD4+ T cell dysfunction in HIV-1 infection is associated with increased CTLA-4 and TGF-β expression. In this study we described a population of TGF-β-positive CD4+ T cells with multiple HIV specificities. These HIV-specific TGF-β-positive CD4+ T cells did not display the immunophenotypic patterns traditionally attributed to regulatory CD4+ T cells. TGF-β-positive CD4+ T cells were FOXP3 negative, CD25 negative, and displayed a heterogeneous surface expression of CD127. We also examined one potential mechanism for regulating TGF-β expression by HIV-specific CD4+ T cells. Blocking of the TGF-β receptor II led to increased HIV-specific IFN-γ-positive CD4+ and CD8+ T cell responses. Interestingly, HIV-specific TGF-β-positive CD4+ T cells did not substantially express CTLA-4. Nevertheless, CTLA-4 blockade resulted in a significant decrease in HIV-specific TGF-β-positive CD4+ T cell responses, and a concomitant increase in HIV-specific IFN-γ-positive CD4+ T cell responses. Our study proposes a mechanism by which HIV-specific TGF-β production may be regulated by CTLA-4 engagement

A Social Media-Based Public Health Campaign to Reduce Indoor Tanning in High-Risk Populations.

INTRODUCTION: Indoor tanning beds cause more than 450,000 new skin cancers each year, yet their use remains common, with a global indoor tanning prevalence of 10.4%. Social media provides an opportunity for cost-effective, targeted public health messaging. We sought to direct Instagram users at high risk of indoor tanning to accurate health information about the risks of indoor tanning and to reduce indoor tanning bed use. METHODS: We disseminated a public health campaign on Instagram on April 6-27, 2022 with 34 video and still-image advertisements. We had 2 target audiences at high risk of indoor tanning: women aged 18-30 years in Kentucky, Nebraska, Ohio, or Tennessee interested in indoor tanning and men aged 18-45 years in California interested in indoor tanning. To evaluate the impact of the campaign, we tracked online metrics, including website visits, and conducted an interrupted time-series analysis of foot traffic data in our target states for all tanning salons documented on SafeGraph from January 1, 2018 to 3 months after the campaign. RESULTS: Our indoor tanning health information advertisements appeared on Instagram feeds 9.1 million times, reaching 1.06 million individuals. We received 7,004 views of our indoor tanning health information landing page (Average Time on Page of 56 seconds). We did not identify a significant impact on foot traffic data on tanning salons. CONCLUSIONS: We show the successful use of social media advertising to direct high-risk groups to online health information about indoor tanning. Future research quantifying tanning visits before and after indoor tanning interventions is needed to guide future public health efforts

TGF-β positive, IL-10 positive, and IFN-γ positive HIV-specific CD8+ T cell populations are distinct.

<p>PBMC were stimulated with HIV peptides then stained with anti-IFN-γ FITC, anti-TGF-β PE, anti-CD3 AmCyan, anti-CD4 PerCP Cy5.5, and anti-CD8 PE Cy7, anti-IL-10 APC, and analyzed by flow cytometry. Samples were first gated on the CD3+/CD8+ lymphocyte population then the percent of TGF-β, IFN-γ, and IL-10 positive CD8+ T cells were determined. (A) Data from individuals with significant cytokine expression and analysis were performed by Mann-Whitney <i>U</i> test. (B) Representative plots of the number of HIV-specific CD8+ T cells expressing TGF-β, IFN-γ, and IL-10 after subtraction of the back ground values.</p

HIV-specific TGF-β and IL-10 positive CD8+ T cells are CTLA-4 negative.

<p>PBMC were stimulated with HIV peptides then stained with anti-TGF-β PE (or IL-10 PE), anti-CD3 AmCyan, anti-CD4 PerCP Cy5.5, anti-CD8 PE Cy7, anti-CTLA-4 APC, and analyzed by flow cytometry. Gating on the CTLA-4 positive cells was performed using the fluorescence-minus-one (FMO) control for CTLA-4. (A) Representative plots of samples that were first gated on the CD3+/CD4+ and CD3+/CD8+ lymphocyte population and then the percentages of CTLA-4 positive cells were determined. (B) Representative plots of samples that were first gated on the CD3+/CD8+ lymphocyte population and then the percent of TGF-β and IL-10 positive cells that express CTLA-4 was determined after subtraction of the back ground values. The values marked with an asterisk represent the fraction of TGF-β (or IL-10) positive cells that express CTLA-4 over the total number of TGF-β (or IL-10) positive cells (equivalent to 100%). Plots are from three independent experiments yielding similar results.</p

Analysis of regulatory surface markers expression by HIV-specific TGF-β positive CD8+ T cells.

<p>PBMC were stimulated with HIV peptides, then stained for various memory and regulatory markers and the percentage of TGF-β positive CD8+ T cells was determined by flow cytometry. Samples were first gated on the CD3+/CD8+ lymphocyte population and then the percentages of TGF-β positive cells were determined and the extent of FOXP3, CD127, CD25, and CD27 expression was also examined. Gating was performed using the fluorescence-minus-one (FMO) control for each marker. Representative plots of the phenotype of the HIV-specific CD8+ T cells expressing TGF-β. The values marked with an asterisk represent the fraction of TGF-β positive cells that express FOXP3, CD127, CD25, or CD27 over the total number of TGF-β positive cells (equivalent to 100%).</p