For optimal quality, memory CD8(+) T cells require CD4(+) T cell help. We have examined whether CD4(+) T cells require CD27 to deliver this help, in a model of intranasal OVA protein immunization. CD27 deficiency reduced the capacity of CD4(+) T cells to support Ag-specific CD8(+) T cell accumulation at the tissue site after primary and secondary immunization. CD27-dependent CD4(+) T cell help ...

T cells have an essential role in the induction of multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE). Although for CD4(+) T cells it is well established that they contribute to the disease, less is known about the role of CD8(+) T cells. Our aim was to determine the individual contribution of CD4(+) and CD8(+) T cells in myelin oligodendrocyte glycoprotein ...

BACKGROUND Although effective antiretroviral therapy(ART) increases CD4+ T-cell count, responses to ART vary considerably and only a minority of patients normalise their CD4+/CD8+ ratio. Although retention of naïve CD4+ T-cells is thought to predict better immune responses, relationships between CD4+ and CD8+ T-cell subsets and CD4+/CD8+ ratio have not been well described. METHODS A cross-sec...

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...

CD4(+) and CD8(+) T cells exhibit important differences in their major effector functions. CD8(+) T cells provide protection against pathogens through cytolytic activity, whereas CD4(+) T cells exert important regulatory activity through production of cytokines. However, both lineages can produce interferon (IFN)-gamma, which can contribute to protective immunity. Here we show that CD4(+) and C...

CD4(+)CD25(+) regulatory T cells inhibit organ-specific autoimmune diseases induced by CD4(+)CD25(-) T cells and are potent suppressors of CD4(+)CD25(-) T cell activation in vitro. We demonstrate that CD4(+)CD25(+) T cells also suppress both proliferation and IFN-gamma production by CD8(+) T cells induced either by polyclonal or Ag-specific stimuli. CD4(+)CD25(+) T cells inhibit the activation ...

CD4(+) T cells promote CD8(+) T cell priming by licensing dendritic cells (DCs) via CD40-CD154 interactions. However, the initial requirement for CD40 signaling may be replaced by the direct activation of DCs by pathogen-derived signals. Nevertheless, CD40-CD154 interactions are often required for optimal CD8(+) T cell responses to pathogens for unknown reasons. Here we show that CD40 signaling...

CD8(+) T cells activated without CD4(+) T-cell help are impaired in memory expansion. To understand the underlying cellular mechanism, here we track the dynamics of helper-deficient CD8(+) T-cell response to a minor histocompatibility antigen by phenotypic and in vivo imaging analyses. Helper-deficient CD8(+) T cells show reduced burst expansion, rapid peripheral egress, delayed antigen clearan...

Abstract Controlled lymphocyte activation is crucial for defending against pathogens while preventing diseases such as autoimmunity and lymphoma. In T lymphocytes, the scaffold protein signaling hub CARD11 mediates NF-κB, JNK, mTOR pathway downstream of cell receptor (TCR) engagement. We recently identified QRICH1 a previously unrecognized interactor recruited to complex TCR engagement discover...

Mature T cells express either CD8 or CD4, defining two physiologically distinct populations of T cells. CD8+ T cells, or killer T-cells, and CD4+ T cells, or helper T cells, effect different aspects of T cell mediated adaptive immunity. Currently, determining the ratio of CD4+ to CD8+ T cells requires flow cytometry or immunohistochemistry. The genomic T cell receptor locus is rearranged during...