Circulating HLA-DR+CD4+ effector memory T cells resistant to CCR5 and PD-L1 mediated suppression compromise regulatory T cell function in tuberculosis
Fig 7
HLA-DR+ and HLA-DR- Teff cells in PTB differ in their capacity to secrete pro-inflammatory cytokines.
PBMC from PTB and IGRA-ve subjects were activated with either PHA or Mtb whole cell lysate. Brefeldin and monensin were added to cultures to prevent cytokine secretion. After 16 hrs of activation, cells were fixed, permeabilised and stained with an antibody cocktail comprising Avid, anti-CD3, anti-CD4, anti-CD45RA, anti-CD127, anti-CD25, anti-HLA-DR, anti-IFNγ anti-IL-2, anti-IL-17A and anti-IL-22. Expression of cytokines was measured in the Avid-CD3+CD4+CD45RA-CD127hiCD25loHLA-DR+ and Avid-CD3+CD4+CD45RA-CD127hiCD25loHLA-DR- Teff compartments. A representative FACS plot of PHA activated PBMC from a PTB donor with cytokine positive cells in the HLA-DR+ and HLA-DR- Teff fractions is shown (A). IFNγ+, IL-2+, IL-17A+ and IL-22+ cells in response to stimulation were measured as a frequency of HLA-DR+ and HLA-DR- Teff cells (B). A total of 9–11 PTB and 6 IGRA-ve donors were used. Paired Wilcoxon matched-pairs signed rank test with Bonferroni correction was used to determine P value. *p ≤ 0.013.