Kinetics of T cell-activation molecules in response to Mycobacterium tuberculosis antigens

Abstract

The phenotypic features acquired subsequent to antigen-specific stimulation in vitro were evaluated by means of the kinetic expressions of CD69 and CD25 activation There has been a concentrated effort over the last few years to characterize specific Mtb molecules for inclusion in a novel TB vaccine and development of more efficacious diagnostic tools. Up to now, evaluations of the functional T cell response in vitro have been based on the secretion of cytokines (mainly IFNγ) and on the expression of activation molecules on the cell surface. Nevertheless, very little information on the phenotypic changes present in the antigen-specific stimulated cells has been made available (Hviid et al. 1993). Based on the recognition of Mtb Ags, the objective of the current study was to evaluate the kinetic expression of early activation molecules (CD69 and CD25) in response to PPD (Statens Serum Institute, Denmark) and the Mtb recombinant proteins Ag85B and ferritin (10 µg/ml) in primary peripheral

Mycobacterium tuberculosis Multidrug Resistant Strain M Induces an Altered Activation of Cytotoxic CD8+ T Cells

“…In contrast to these studies, we showed that strain M did not inhibit TCR signaling and CD69 expression in CD8 + T cells even when this strain was present along the entire culture. In addition, we found no differences in the kinetic of CD69 expression, suggesting that its low expression is not due to a delayed CD8 + T cells activation caused by strain M, as it was observed with other mycobacterial antigens [30]; however, we can not rule out the involvement of other co-stimulatory molecules. Signaling trough CD69 controls IL-2 and IFN-γ gene expression at the transcriptional levels [45], [46] as well as Stat-5 mediated IL-2 signaling.…”

“…In contrast CD25 expression was not modified (data not shown). Given that CD4 + and CD8 + T cells stimulated with mycobacterial antigens show delayed kinetic in CD69 and CD25 expression compared to PHA stimulation in PPD + N [30], we wondered if the low CD69 expression could be due to a delay in CD8 + T cells activation. Thus, the kinetics of CD69 and CD25 expression (1–5 d) in PBMC cultured with Mtb strains were determined.…”

Interferon-γ Low Producer Genotype +874 Overrepresented in Bacillus Calmette-Guerin Nonresponding Children

“…Up to now, evaluations of the functional T cell response in vitro have been based on the secretion of cytokines, mainly IFN-␥, and on the expression of activation molecules on the cell surface. 25 Testing peripheral blood for genetic markers that control the production of inflammatory cytokines such as IFN-␥ may be a better predictor of the outcome of vaccination with BCG. The association between IFN-␥ (ϩ874T/A) polymorphism and production of IFN-␥ by PBMC stimulated with Ag85A, observed in this study indicate the role of polymorphism within the cytokine gene as a marker for identifying individuals at risk for the disease.…”

AFM‐ and NSOM‐based force spectroscopy and distribution analysis of CD69 molecules on human CD4+ T cell membrane

“…In response to phytohaemagglutinin (PHA) stimulation in vitro, CD69 is an early T cell activation marker transiently expressed on T cells. CD69 expression occurs remarkably at 4 h, peaked at 24 h, and quickly decreased at 120 h (Antas et al, 2002). In vivo activation of T cells also induces expression of CD69.…”