To study the steps in the differentiation of human memory CD4 T cells, we characterized the functional and lineage relationships of three distinct memory CD4 subpopulations distinguished by their expression of the cysteine chemokine receptor CCR7 and the TNFR family member CD27. Using the combination of these phenotypic markers, three populations were defined: the CCR7+CD27+, the CCR7-CD27+, and the CCR7-CD27- population. In vitro stimulation led to a stepwise differentiation from naive to CCR7+CD27+ to CCR7-CD27+ to CCR7-CD27-. Telomere length in these subsets differed significantly (CCR7+CD27+ > CCR7-CD27+ > CCR7-CD27-), suggesting that these subsets constituted a differentiative pathway with progressive telomere shortening reflecting antecedent in vivo proliferation. The in vitro proliferative response of these populations declined, and their susceptibility to apoptosis increased progressively along this differentiation pathway. Cytokine secretion showed a differential functional capacity of these subsets. High production of IL-10 was only observed in CCR7+CD27+, whereas IFN-gamma was produced by CCR7-CD27+ and to a slightly lesser extent by CCR7-CD27- T cells. IL-4 secretion was predominantly conducted by CCR7-CD27- memory CD4 T cells. Thus, by using both CCR7 and CD27, distinct maturational stages of CD4 memory T cells with different functional activities were defined.
Mycobacterium tuberculosis causes human tuberculosis. As mycobacteria are protected by thick lipid cell wall, humans have developed immune responses against diverse mycobacterial lipids. Most of these immunostimulatory lipids are known as adjuvants acting through innate immune receptors, such as C-type lectin receptors.
Exonuclease 1 (EXO1) is an evolutionarily conserved exonuclease, which have function on maintaining genomic stability. Elevated expression of EXO1 has been reported in certain cancers. However, a comprehensive pan-cancer analysis of EXO1 is still lacking and its role in human cancer development remains poorly understood.
Department of Nutrition, University of California, Davis, Davis, CA, United States; USDA Western Human Nutrition Research Center, University of California, Davis, Davis, CA, United States. Electronic address:
Background: Immune function is affected by vitamin D status but the optimal serum 25-hydroxy vitamin D [25(OH)D] level for immune function is not known.
Objectives: We hypothesized that 25(OH)D would be associated with markers of inflammation and immune activation.
Methods: We identified associations between 25(OH)D and immune markers from 361 healthy adults using polynomial regression.
This study aims to characterize the majority of immune cell subsets in peripheral blood mononuclear cells in children with Mycoplasma pneumoniae pneumonia (MPP) by a 21-color flow cytometry panel. Patients who met the predetermined eligibility criteria for pneumonia diagnosis were recruited for the research study. Multi-color flow cytometry was conducted on the peripheral blood mononuclear cells of each patient group, which were then subjected to dimensionality reduction and cluster analysis.
