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Adoptive cell therapy with engineered T cells to improve natural immune response and antitumor functions has shown promise for treating cancer. However,the requirement for extensive ex vivo manipulation of T cells and the immunosuppressive effects of the tumor microenvironment limit this therapeutic modality. In the present study,we investigated the possibility to circumvent these limitations by engineering Stat3 -deficient CD8(+) T cells or by targeting Stat3 in the tumor microenvironment. We show that ablating Stat3in CD8(+) T cells prior to their transfer allows their efficient tumor infiltration and robust proliferation,resulting in increased tumor antigen-specific T-cell activity and tumor growth inhibition. For potential clinical translation,we combined adoptive T-cell therapy with a Food and Drug Administration-approved tyrosine kinase inhibitor,sunitinib,in renal cell carcinoma and melanoma tumor models. Sunitinib inhibited Stat3 in dendritic cells and T cells and reduced conversion of transferred FoxP3(-) T cells to tumor-associated regulatory T cells while increasing transferred CD8(+) T-cell infiltration and activation at the tumor site,leading to inhibition of primary tumor growth. These data show that adoptively transferred T cells can be expanded and activated in vivo either by engineering Stat3-silenced T cells or by targeting Stat3 systemically with small-molecule inhibitors. View Publication

The T-cell functions of a proliferation-inducing ligand (APRIL,also known as TNFSF13) remain largely undefined. We previously showed that APRIL suppressed Th2 cytokine production in cultured CD4(+) T cells and Th2 antibody responses. Here we show that APRIL suppresses allergic lung inflammation,which is associated with diminished expression of the transcription factor c-maf. Mice deficient in the April gene (April(-/-) mice) had significantly aggravated lung inflammation compared with WT mice in the ovalbumin-induced allergic lung inflammation model. Likewise,blockade of APRIL in WT mice by the APRIL-receptor fusion protein,transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI)-Ig,enhanced lung inflammation. Transfer of APRIL-sufficient,ovalbumin-specific,TCR-transgenic CD4(+) T (OT-II) cells to April(-/-) mice restored the suppressive effect of APRIL on lung inflammation. Mechanistically,the expression of the Th2 cytokine transcription factor c-maf,but not GATA-3,was markedly enhanced in April(-/-) CD4(+) T cells at the RNA and protein level and under non-polarizing (Th neutral,ThN) and Th2-polarizing conditions. Since c-maf transactivates the IL-4 gene,the increased c-maf expression in April(-/-) mice readily explains increased Th2 cytokine production. Independent of its effect on IL-4,APRIL suppressed IL-13 expression. APRIL thus may regulate lung inflammation in a dual way,by acting on c-maf expression and by directly controlling IL-13 production. View Publication

B1 cells differ in many ways from conventional B cells,most prominently in the production of natural immunoglobulin,which is vitally important for protection against pathogens. B1 cells have also been implicated in the pathogenesis of autoimmune dyscrasias and malignant diseases. It has been impossible to accurately study B1 cells during health and illness because the nature of human B1 cells has not been successfully defined. This has produced controversy regarding the existence of human B1 cells. Here,we determined the phenotype of human B1 cells by testing sort-purified B cell fractions for three fundamental B1 cell functions based on mouse studies: spontaneous IgM secretion,efficient T cell stimulation,and tonic intracellular signaling. We found that a small population of CD20(+)CD27(+)CD43(+) cells present in both umbilical cord and adult peripheral blood fulfilled these criteria and expressed a skewed B cell receptor repertoire. These B cells express little or no surface CD69 and CD70,both of which are markedly up-regulated after activation of CD20(+)CD27(-)CD43(-) (naive) and CD20(+)CD27(+)CD43(-) (memory) B cells. This work identifies human B1 cells as CD20(+)CD27(+)CD43(+)CD70(-). We determined that the proportion of B1 cells declines with age,which may contribute to disease susceptibility. Identification of human B1 cells provides a foundation for future studies on the nature and role of these cells in human disease. View Publication

Recent compelling evidence indicates that Th17 confer host immunity against a variety of microbes,including extracellular and intracellular pathogens. Therefore,understanding mechanisms for the induction and activation of Ag-specific Th17 is important for the rational design of vaccines against pathogens. To study this,we employed an in vitro system in which influenza hemagglutinin (HA) 1 was delivered to dendritic cells (DCs) via Dectin-1 using anti-human Dectin-1 (hDectin-1)-HA1 recombinant fusion proteins. We found that healthy individuals maintained broad ranges of HA1-specific memory Th17 that were efficiently activated by DCs targeted with anti-hDectin-1-HA1. Nonetheless,these DCs were not able to induce a significant level of HA1-specific Th17 responses even in the presence of the Th17-promoting cytokines IL-1? and IL-6. We further found that the induction of surface IL-1R1 expression by signals via TCRs and common ?-chain receptors was essential for naive CD4(+) T cell differentiation into HA1-specific Th17. This process was dependent on MyD88,but not IL-1R-associated kinase 1/4. Thus,interruptions in STAT3 or MyD88 signaling led to substantially diminished HA1-specific Th17 induction. Taken together,the de novo generation of pathogen-specific human Th17 requires complex,but complementary,actions of multiple signals. Data from this study will help us design a new and effective vaccine strategy that can promote Th17-mediated immunity against microbial pathogens. View Publication

Background Progressive T cell decline in aged humans is associated with a deficiency of naive (TN) and central memory (TCM) T cells. We have previously reported increased tumor necrosis factor-? (TNF-?)-induced apoptosis in TN and TCM T cells in aged humans; however,the molecular basis of increased apoptosis remains to be defined. Since expression of TNF receptors (TNFRs) was reported to be comparable in young and aged,we investigated signaling events downstream of TNFRs to understand the molecular basis of increased TNF-?-induced apoptosis in aged TN and TCM CD8+ cells. Results The expression of TRAF-2 and RIP,phosphorylation of JNK,IKK?/?,and I?B?,and activation of NF-?B activation were significantly decreased in TN and TCM CD8+ cells from aged subjects as compared to young controls. Furthermore,expression of A20,Bcl-xL,cIAP1,and FLIP-L and FLIP-S was significantly decreased in TN and TCM CD8+ cells from aged subjects. Conclusions These data demonstrate that an impaired expression/function of molecules downstream TNFR signaling pathway that confer survival signals contribute to increased apoptosis of TN and TCM CD8+ cells in aged humans. View Publication