Detection of the CD8+ T cell immune response in mice infected with OVA-Listeria monocytogenes.

T cells are able to recognize and kill pathogens that infect host cells, including bacteria, viruses, and tumor cells. Here, we present a protocol to detect T cell function and bacterial load in OVA-Listeria monocytogenes-infected mice. We provide a detailed description of the steps for detecting OVA-specific CD8+ T cells and their cytokine expression levels in splenocytes using flow cytometry on day 7 after infecting mice with OVA-Listeria monocytogenes. Additionally, we describe the steps for detecting the OVA-Listeria monocytogenes load in the mouse liver. For complete details on the use and execution of this protocol, please refer to Chen et al.1.

Increased pro-inflammatory cytokine-secreting regulatory T cells are correlated with the plasticity of T helper cell differentiation and reflect disease status in asthma.

BACKGROUND: Human regulatory T cells (Tregs) are a heterogeneous population which consists of three distinct subpopulations: CD25+CD45RA+ resting Treg (rTreg) cells; CD25hiCD45RA- activated Treg (aTreg) cells, which are both suppressive; and CD25+CD45RA- cytokine-secreting T cells with pro-inflammatory capacity. OBJECTIVE: We investigated variation in peripheral Treg subpopulations of asthma and explored their potential roles in asthma inflammation. METHODS: Twenty-eight mild asthma patients, 26 moderate asthma patients, 18 severe asthma patients, and 36 healthy controls were recruited for a cross-sectional study. Phenotyping of peripheral CD4+ Tregs was performed based on flow cytometry results. RESULTS: The proportions of rTreg and aTreg cells among CD4+ T cells were higher in mild and moderate asthma patients than in healthy controls. All three groups of asthmatics had a higher proportion of pro-inflammatory Tregs than healthy controls, and these increased with asthma severity. The proportion of IL-17-producing Foxp3+ cells and IFN-ɤ-producing Foxp3+ cells strongly correlated with T helper 17 (Th17) cells (r = 0.66, p < 0.001) and Th1 cells (r = 0.48, p < 0.001). The pro-inflammatory Treg subpopulation was correlated with the severity of asthma and may be insensitive to corticosteroids. CONCLUSIONS: Our data suggest that pro-inflammatory Treg subpopulations may be relevant to the plasticity of Th17 and Th1 differentiation and play an important role in the pathogenesis of asthma.