A model of chemical thymectomy by inducible Rag ablation was used to study peripheral T cell homeostasis. Induction of Rag ablation was efficient and complete, leading to cessation of thymic T cell production within 3-4 weeks. The decay of peripheral T cells became apparent with a delay of an additional 2-3 weeks and was entirely accounted for by loss of naïve T cells, whereas numbers of memory...

Antigen inexperienced (naïve) CD4(+) T cells undergo expansion and differentiation to effector subsets at the time of T cell receptor (TCR) recognition of cognate antigen presented on MHC class II. The cytokine signals present in the environment at the time of TCR activation are a major factor in determining the effector fate of a naïve CD4(+) T cell. Although the cytokine environment during na...

Recent reports suggest dyslipidemia impairs dendritic cell (DC) function and adaptive immunity. This study aimed to characterize the effect of hypercholesterolemia on antigen-presenting cell function of DCs and DC-dependent CD4(+) T-cell responses. DCs incubated in vitro with acetylated low-density lipoprotein cholesterol with or without an acyl-coenzyme A:cholesterol acyl-transferase inhibitor...

CD4 T-cell help is required for the induction of efficient CD8 T-cells responses and the generation of memory cells. Lack of CD4 T-cell help may contribute to an exhausted CD8 phenotype and viral persistence. Little is known about priming of CD4 T-cells by liver-derived antigen. We used TF-OVA mice expressing ovalbumin in hepatocytes to investigate CD4 T-cell priming by liver-derived antigen an...

The signaling pathways utilized by naïve and experienced effector CD4 T cells during activation and proliferation were evaluated. While inhibition of either mTOR or MAPK alone was able to inhibit naïve T cell proliferation, both mTOR and MAPK (ERK) pathway inhibition was required to efficiently block experienced, effector CD4 T cell proliferation. This was demonstrated both in vitro, and in viv...

Intestinal inflammation can be induced by the reconstitution of T/B cell-deficient mice with low numbers of CD4(+) T lymphocytes depleted of CD25(+)Foxp3(+) regulatory T cells (Treg). Using RAG-knockout mice as recipients of either splenocytes exclusively depleted of CD25(+) cells or FACS-purified CD4(+)CD25(-)Foxp3(-) T cells, we found that the augmentation of potentially colitogenic naïve T c...

GBV-C infection is associated with prolonged survival and with reduced T cell activation in HIV-infected subjects not receiving combination antiretroviral therapy (cART). The relationship between GBV-C and T cell activation in HIV-infected subjects was examined. HIV-infected subjects on cART with non-detectable HIV viral load (VL) or cART naïve subjects were studied. GBV-C VL and HIV VL were de...

The naïve CD4+ T-cell compartment is considered essential to guarantee immune competence throughout life. Its replenishment with naïve cells with broad diverse receptor repertoire, albeit with reduced self-reactivity, is ensured by the thymus. Nevertheless, cumulative data support a major requirement of post-thymic proliferation both for the establishment of the human peripheral naïve compartme...

BACKGROUND To investigate the clinical significance of naïve T cells, memory T cells, CD45RA+CD45RO+ T cells, and naïve/memory ratio in non-small cell lung cancer (NSCLC) patients. METHODS Pretreatment peripheral blood samples from 76 NSCLC patients and 28 age- and sex-matched healthy volunteers were collected and tested for immune cells by flow cytometry. We compared the expression of these ...

Abstract Mounting evidence supports a role for the immune system in pathophysiology of dementia. Alterations composition circulating cells is one key changes associated with age. However, age and sex on cell phenotypes their contribution to disease pathogenesis remains be unraveled. We identified study sample 996 participants (mean 62 years, range 40 88 52% female, 22% APOE-ϵ4 carriers) from co...