Anti-TBX21 monoclonal antibody, clone 5C21

The onset of protective immunity against pathogenic SIV challenge in SIV Delta nef-vaccinated macaques is delayed for 15-20 weeks, a process that is related to qualitative changes in CD8(+) T cell responses induced by SIV Delta nef. As a novel approach to characterize cell differentiation following vaccination, we used multi-target qPCR to measure transcription factor expression in naive and memory subsets of CD8+(+) T cells, and in SIV-specific CD8(+) T cells obtained from SIV Delta nef-vaccinated or wild type SIVmac239-infected macaques. Unsupervised clustering of expression profiles organized naive and memory CD8(+) T cells into groups concordant with cell surface phenotype. Transcription factor expression patterns in SIV-specific CD8(+) T cells in SIV Delta nef-vaccinated animals were distinct from those observed in purified CD8(+) T cell subsets obtained from naive animals, and were intermediate to expression profiles of purified central memory and effector memory T cells. Expression of transcription factors elicited by SIV Delta nef vaccination also varied over time: cells obtained at later time points, temporally associated with greater protection, appeared more central-memory like than cells obtained at earlier time points, which appeared more effector memory-like. Expression of transcription factors associated with effector differentiation, such as ID2 and RUNX3, were decreased over time, while expression of transcription factors associated with quiescence or memory differentiation, such as TCF7, BCOR and EOMES, increased. CD8(+) T cells specific for a more conserved epitope expressed higher levels of TBX21 and BATF, and appeared more effector-like than cells specific for an escaped epitope, consistent with continued activation by replicating vaccine virus. These data suggest transcription factor expression profiling is a novel method that can provide additional data complementary to the analysis of memory cell differentiation based on classical phenotypic markers. Additionally, these data support the hypothesis that ongoing stimulation by SIV Delta nef promotes a distinct protective balance of CD8(+) T cell differentiation and activation states.

The mechanisms underlying mesenchymal stem cells' (MSC) suppressive potency are largely unknown. We here show that highly suppressive human adipose tissue-derived MSC (AdMSC) display and induce a differential immunologic profile, upon ongoing AdMSC suppressive activity, promoting: (i) early correlated inhibition of IFN-gamma and TNF-alpha production, along IL-10 increase, (ii) CD73(+) Foxp3(+) Treg subset expansion, and (iii) specific correlations between gene expression increases, such as: MMP9 correlated with CCL22, TNF, FASL, RUNX3, and SEMAD4 in AdMSC and, in T cells, MMP9 upregulation correlated with CCR4, IL4 and TBX21, among others, whereas MMP2 correlated with BCL2 and LRRC31. MMP9 emerged as an integrating molecule for both AdMSC and T cells in molecular networks built with our gene expression data, and we confirmed upregulation of MMP9 and MMP2 at the protein level, in AdMSC and T cells, respectively. MMP2/9 inhibition significantly decreased AdMSC suppressive effect, confirming their important role in suppressive acitivity. We conclude that MMP9 and 2 are robust new players involved in human MSC immunoregulatory mechanisms, and the higher suppressive activity correlates to their capacity to trigger a coordinated action of multiple specific molecules, mobilizing various immunoregulatory mechanisms.