Cutting edge: a critical role for CD70 in CD8 T cell priming by CD40-licensed APCs

The CD154/CD40 interaction is an important pathway of CD4 T cell help for CD8 T cell responses. In this study, we address the role of CD70, a member of the TNF superfamily and the ligand for the T cell costimulatory receptor CD27, in CD40-mediated priming of CD8 T cells. Using an agonistic anti-CD40 mAb to mimic the CD154/CD40 interaction we demonstrate that the priming of OT-I TCR transgenic or endogenous mouse OVA-specific CD8 T cells is critically dependent on CD70/CD27 interaction. CD70 blockade inhibited CD40-mediated clonal expansion of CD8 T cells and reduced the number of memory CD8 T cells generated. Furthermore, CD70 blockade during the initial priming of CD8 T cells inhibited the ability of memory CD8 T cells to expand in response to a second encounter with Ag. Our data indicate that CD70 expression on APCs plays a key role in CD40-dependent CD8 T cell responses

Differential impact of CD27 and 4-1BB costimulation on effector and memory CD8 T cell generation following peptide immunization

The factors that determine differentiation of naive CD8 T cells into memory cells are not well understood. A greater understanding of how memory cells are generated will inform of ways to improve vaccination strategies. In this study, we analyzed the CD8 T cell response elicited by two experimental vaccines comprising a peptide/protein Ag and an agonist that delivers a costimulatory signal via CD27 or 4-1BB. Both agonists increased expansion of Ag-specific CD8 T cells compared with Ag alone. However, their capacity to stimulate differentiation into effector and memory cells differed. CD27 agonists promoted increased expression of perforin and the generation of short-lived memory cells, whereas stimulation with 4-1BB agonists favored generation of stable memory. The memory-promoting effects of 4-1BB were independent of CD4 T cells and were the result of programing within the first 2 d of priming. Consistent with this conclusion, CD27 and 4-1BB–stimulated CD8 T cells expressed disparate amounts of IL-2, IFN-?, CD25, CD71, and Gp49b as early as 3 d after in vivo activation. In addition, memory CD8 T cells, generated through priming with CD27 agonists, proliferated more extensively than did 4-1BB–generated memory cells, but these cells failed to persist. These data demonstrate a previously unanticipated link between the rates of homeostatic proliferation and memory cell attrition. Our study highlights a role for these receptors in skewing CD8 T cell differentiation into effector and memory cells and provides an approach to optimize vaccines that elicit CD8 T cell responses

Cell therapy of brain stroke

Cell suspension consisting of cells from immature nervous and hemopoietic tissues was subarachnoidally transplanted to 10 patients with brain stroke consequences. Clinical effect of different degree was attained in all patients. Six months after cell therapy functional activity significantly increased in contrast to clinically comparable control group. No serious complications of cell therapy were observed. Presumably, cell therapy is a more or less safe method of treatment, which can be effectively used in the treatment of brain stroke consequences

Bone marrow cells in suppressing leukemic cell growth

In this paper we review our experimental findings concerning the capacity of bone marrow cells (BMC) to control leukemic cell growth. It has been shown that the cells isolated from normal bone marrow can provide dose dependent suppression of the proliferative activity of leukemic cells in vitro. BMC cytostatic effect is antigen non-specific and does not associate with cell death. Cytostatic BMC differ from mature macrophages, T and B lymphocytes and have the lower floating density. These cells are detected in both aggregated and non-aggregated fraction of BMC, stimulated by wheat germ agglutinin. During long-term cultivation of bone marrow the cytostatic activity was associated with the radioresistant stromal cells. Both soluble factors and cell-to-cell interactions are involved into the cytostatic process generated by BMC. Based on the obtained results, we suggest that the cytostatic activity of BMC may be increased under the influence of lymphokines, such as IL-2 and IFNgamma

CD27 costimulation contributes substantially to the expansion of functional memory CD8+ T cells after peptide immunization

Naive T cells require signals from multiple costimulatory receptors to acquire full effector function and differentiate to long-lived memory cells. The costimulatory receptor, CD27, is essential for optimal T-cell priming and memory differentiation in a variety of settings although whether CD27 is similarly required during memory CD8+ T-cell re-activation remains controversial. We have used OVA and anti-CD40 to establish a memory CD8+ T-cell population and report here that their secondary expansion, driven by peptide and anti-CD40, polyI:C or LPS requires CD27. Furthermore, antigenic peptide and a soluble form of the CD27 ligand, CD70 (sCD70), is sufficient for secondary memory CD8+ T-cell accumulation at multiple anatomical sites, dependent on CD80/86. Prior to boost, resting effector- and central-memory CD8+ T cells both expressed CD27 with greater expression on central memory cells. Nonetheless both populations upregulated CD27 after TCR engagement and accumulated in proportion after boosting with antigen and sCD70. Mechanistically, sCD70 increased the frequency of divided and cytolytic memory T cells, conferred resistance to apoptosis and enabled retardation of tumor growth in vivo. These data demonstrate the central role played by CD27/70 during secondary CD8+ T-cell activation to a peptide antigen, and identify sCD70 as an immunotherapeutic adjuvant for anti-tumor immunit

Integrin beta2-phosphorylation on Thr758 acts as a molecular switch to regulate 14-3-3 and filamin binding

This paper looks at the effects of dust allergen and LPS concentrations on biomarkers of asthma in adults with house dust mite-sensitive asthma

Sustained TL1A expression modulates effector and regulatory T-cell responses and drives intestinal goblet cell hyperplasia

The tumor necrosis factor (TNF) superfamily protein TNF-like 1A (TL1A) is the ligand for death receptor 3 (DR3). TL1A is induced on activated dendritic cells (DCs) and its expression has been linked to human inflammatory bowel disease. To address how TL1A might influence intestinal inflammation, we generated transgenic mice that constitutively express TL1A on DCs. TL1A transgenic mice developed striking goblet cell hyperplasia in the ileum that was associated with elevated interleukin (IL)-13 levels in the small intestine. IL-13- and IL-17-producing small intestinal lamina propria T cells were increased in TL1A transgenic mice. TL1A also enhanced regulatory T (Treg) cell turnover in vivo and directly stimulated Treg cell proliferation in vitro. The presence of TL1A attenuated the ability of Treg cells to suppress conventional T cells, an effect that required DR3 signaling in either conventional T cells or Treg cells. Our findings identify mechanisms by which chronic DR3 signaling could promote pathogenesis in inflammatory bowel disease