Data were collected using an LSRII movement cytometer (BD Biosciences, San Jose, CA), and analyzed using the FlowJo software program (TreeStar, Ashland, OR)
June 16, 2021
Data were collected using an LSRII movement cytometer (BD Biosciences, San Jose, CA), and analyzed using the FlowJo software program (TreeStar, Ashland, OR). Statistical analysis For all experiments, the dam is defined as the statistical unit. and metabolic pathways were associated with triggering AHR during development. Functional bioassays confirmed that CD4+ T cells from infected developmentally exposed offspring exhibit reduced proliferation, differentiation, and cellular metabolism. Thus, developmental AHR activation shapes T cell responsive capacity later in life by affecting integrated cellular pathways, which collectively alter responses later in life. Given that coordinated shifts in T cell metabolism are essential for T cell responses to numerous challenges, Nrp1 and that humans are constantly exposed to many different types of AHR ligands, this has ZM 39923 HCl far-reaching implications for how AHR signaling, particularly during development, durably influences T cell mediated immune responses across the lifespan. and approaches. We developmentally exposed mice to vehicle or TCDD, and measured clonal expansion of CD4+ T cells specific for viral nucleoprotein (NP) peptide (311C325) after IAV challenge. Compared to offspring of control dams, the number of NP-specific CD4+ T cells was significantly lower 6, 9 and 12 days after IAV infection in adult offspring of TCDD-exposed dams (Fig.?3b). Nine days after infection, which is the height of the T cell response to IAV, we determined the number and percentage of proliferating CD4+ T cells using the marker Ki67. Consistent with fewer NP+CD4+ T cells, developmental AHR activation significantly reduced the number and percentage of proliferating CD4+ T ZM 39923 HCl cells (Fig.?3c,d). Open in a separate window Figure 3 TCDD exposure during development impairs CD4+ T cell proliferation. (a) IPA predicted pathways involved in cellular proliferation. The heat map shows genes that are differentially expressed following developmental AHR activation in resting and responding CD4+ T cells. Genes were ordered using unsupervised clustering by row. See Supplemental Table?2 for gene list. (bCd) Adult offspring from Vehicle (V) and TCDD (T) exposed dams were infected with IAV. (b) Virus specific CD4+ T MLN cells were enumerated using flow cytometry on days 6, 9, and 12 post-infection using MHCII tetramers (I-Ab/NP311C325). (c,d) Proliferating Ki67+CD4+ T cells were assessed on day 9 post-infection. Bar graph shows the (c) number in vehicle (white bar) and TCDD (orange bar) groups. The histogram shows the (d) percentage of CD4+ T cells that are Ki67+ in vehicle (grey histogram) and TCDD (orange histogram) mice. (eCh) CD4+ T cells were isolated from peripheral lymph nodes of na?ve vehicle (grey dots) and TCDD (orange dots) developmentally exposed animals. Cells were stained with CFSE and stimulated in culture for (e,f) four or (g,h) three days with (e,g) 5?g/mL or (immune challenge, but mitogenic stimulation can overcome this defect. Thus, while pathways that drive T cell proliferation are affected by developmental exposure, the cell proliferation machinery within CD4+ T cells is operational. CD4+ T cell differentiation is impacted by developmental AHR activation Genes related to T cell differentiation were also altered by developmental exposure in both resting and responding CD4+ T cells (Fig.?4a). Interestingly, many of the genes that were up-regulated ZM 39923 HCl in vehicle responding CD4+ T were also up-regulated in resting, but not responding, CD4+ T cells from mice developmentally exposed to TCDD. A full list of DEGs related to differentiation can be found in Supplemental Table?3. Therefore, in addition to diminishing proliferation, the reduced number of Th1, Tfh, and Th17 cells (Fig.?1aCc) could be the result of impaired T cell differentiation. Triggering the AHR during development significantly reduced the percentage of Th1 and Tfh cells during IAV infection at adulthood (Fig.?4b,c). Compared to the two Th subtypes that predominate during acute primary IAV infection, the percentage of Th17s was not significantly different in the two groups of offspring (Fig.?4d). Often when the percentage of Th1 cells declines, there is a compensatory increase in Th2 cells. However, developmental AHR activation reduced the percentage of Th2 cells during IAV infection (Fig.?4e). There is another CD4+ T cell subset known as regulatory T cells (Tregs) that help maintain peripheral tolerance and promote resolution after viral infections26. The proper balance of immunostimulatory:immunoregulatory CD4+ T cell subsets is critical for a properly functioning immune system. Following developmental AHR activation, the percentage of Tregs was increased during IAV infection?(Fig. 4f). Thus, consistent with prior reports, AHR activation impacts CD4+ T cell differentiation during IAV infection22. Open in a separate window Figure 4 CD4+ T cells from mice developmentally exposed to TCDD do not have a differentiation defect in culture. (a) Heat map shows differentiation related DEGs. Genes are ordered using unsupervised clustering by row. See Supplemental Table?3 for gene list. (bCf) Offspring that were developmentally exposed to vehicle or TCDD were infected with IAV at.