Ag-Specific Type 1 CD8 Effector Cells Enhance Methotrexate-Mediated Antitumor Responses by Modulating Endogenous CD49b-Expressing CD4 and CD8 T Effector Cell Subpopulations Producing IL-10

The chemotherapeutic agent methotrexate is widely used in the treatment of breast cancer. Although its mechanism-of-action has been defined, less is known about its interaction with Ag-specific T cell-mediated antitumor responses. Type 1 CD8 T cell-mediated immune responses (Tc1) are cytolytic, produce IFN-gamma and are associated with effective antitumor responses. Using a murine transgenic TCR tumor model, we show that single-dose-treatment with methotrexate enhanced CD8-mediated type 1 antitumor responses when administered three days prior to Tc1 effector cell transfer. Co-treatment with methotrexate not only enhanced donor Tc1 cell accumulation and persistence at sites of primary tumor growth, but also promoted elevated levels of activated CD25⁺ expressing donor TIL cells. This correlated with a marked decrease in the appearance of endogenous differentiated (CD44^High) CD3/CD8/CD49b and CD3/CD4/CD49b tumor-infiltrating effector T cells at both early (Days 1–8) and late (Days 12–20) stages following treatment when compared to that of corresponding groups receiving either MTX or Tc1 cell transfer alone. Moreover, such cellular response kinetics appeared to further correlate with the down-regulation of endogenous CD4/CD44^High/CD49b effector T cells producing IL-10 and delays in tumor growth in vivo. This suggested that Ag-specific Tc1 cell transfer, in combination with chemotherapy, can enhance antitumor responses by modulating select CD49b-expressing T effector/memory cell subpopulations involved in homeostasis and immune tolerance within the tumor environment. These studies offer insight into mechanisms that enhance T cell-based immunotherapy in cancer. Supplementary materials are available for this article. Go to the publisher's online edition of Immunological Investigations for the following free supplemental resource(s): Addendum 1.     

Notch1 expression on T cells is not required for CD4+ T helper differentiation

Notch1 proteins are involved in binary cell fate decisions. To determine the role of Notch1 in the differentiation of CD4(+) Th1 versus Th2 cells, we have compared T helper polarization in vitro in naive CD4(+) T cells isolated from mice in which the N1 gene is specifically inactivated in all mature T cells. Following activation, Notch1-deficient CD4(+) T cells transcribed and secreted IFN-gamma under Th1 conditions and IL-4 under Th2 conditions at levels similar to that of control CD4(+) T cells. These results show that Notch1 is dispensable for the development of Th1 and Th2 phenotypes in vitro. The requirement for Notch1 in Th1 differentiation in vivo was analyzed following inoculation of Leishmania major in mice with a T cell-specific inactivation of the Notch1 gene. Following infection, these mice controlled parasite growth at the site of infection and healed their lesions. The mice developed a protective Th1 immune response characterized by high levels of IFN-gamma mRNA and protein and low levels of IL-4 mRNA with no IL-4 protein in their lymph node cells. Taken together, these results indicate that Notch1 is not critically involved in CD4(+) T helper 1 differentiation and in resolution of lesions following infection with L. major.     

Absence of significant Th2 response in diabetes-prone non-obese diabetic (NOD) mice.

Accumulating evidence suggests that Th1 T cells play a pivotal role in the development of autoimmune diabetes. Conversely, promoting a Th2 response inhibits disease progression. However, it has not been determined whether Th2 cells are regulatory T cells that fail at the time of diabetes development in naive non-diabetic NOD mice. Therefore, in order to evaluate cytokine secretion by spleen and islet infiltrating T cells in NOD mice at different stages of the autoimmune process, we developed an ELISPOT assay that detects IL-2, IL-4, and interferon-gamma (IFN-gamma) secretion in vitro at the single-cell level. We showed that, whatever the age considered, IFN-gamma is predominantly secreted, and that no IL-4-secreting cells are detected in the islets of male and female NOD mice. Spleen cells from 8-week-old female NOD mice, which include regulatory suppressor T cells, do not secrete IL-4, either upon presentation of islet cell antigens in vitro, or after transfer in vivo, but do secrete IFN-gamma. IFN-gamma secretion by T cells from diabetic mice results from CD4 but not CD8 T cells in transfer experiments into NOD/severe combined immunodeficient (SCID) recipients. These results suggest that (i) detection of regulatory CD4 T cells in NOD mice is not paralleled by a Th2 response; (ii) beta cell destruction does not depend on a switch from a Th2 to a Th1-type response; and (iii) CD8 T cells do not participate in induction of diabetes by secreting IFN-gamma.     

Th17细胞介导肿瘤免疫的双向性及其意义

Th17细胞作为众多CD4+辅助性T细胞的一种,其标志性特点是能分泌炎性因子白细胞介素(IL-17)参与炎症反应.随着人们对炎症的深入了解,发现Th17细胞不只是发挥炎性效应,其在肿瘤的发生、发展及抗肿瘤方面也有重要的作用.研究发现,在多种肿瘤中存在Th17细胞及其相关的细胞因子,Th17细胞分泌炎性因子IL-17主动增强相关的抗肿瘤信号通路,调控抗肿瘤免疫应答.另外,固有免疫细胞IL-17+γδT细胞以及IL-17+ Foxp3T细胞不仅分泌IL-17发挥促肿瘤效应,还能协同Th17细胞参与到抗肿瘤免疫反应中,共同调控机体的抗肿瘤免疫反应.因而研究Th17细胞参与肿瘤应答的机制以及与IL-17+γδT细胞和IL-17+ Foxp3T细胞在肿瘤免疫中的相互作用关系具有重要意义.     

慢性乙肝患者树突状细胞对Th1/Th2分化的影响

探讨慢性乙肝患者树突状细胞(dendritic cells,DC)对CD4+Th细胞亚群分化的影响。分离慢性乙肝患者外周血单个核细胞(PBMC),以rhIL-4(50 ng/ml)、rhGM-CSF(10 ng/ml)和rhTNF-α(100 u/ml)诱导培养DC。以流式细胞仪检测DC表面CD1a、CD83、CD80、CD86、HLA-DR分子表达情况。MTT法检测DC刺激同种异体淋巴细胞增殖能力。免疫磁珠分离外周血CD4+T细胞亚群,PMA+Ionomycin刺激后胞内荧光染色,流式细胞仪检测辅助性T细胞(helper T cell,Th)内特征性细胞因子IFN-γ/IL-4以判断Th1/Th2分化。ELISA法检测DC或Th细胞培养上清中IL-6、IL-12、IFN-γ和IL-4的含量。结果:慢性乙肝患者的DC表达CD1a、CD83、CD80、CD86、HLA-DR分子水平明显低于正常人(P<0.01);培养至第7天,慢性乙肝患者DC分泌的IL-12水平低于正常人(P<0.01),而分泌的IL-6水平增高(P<0.05)。与正常人相比,慢性乙肝患者外周血中Th1细胞占CD4+T细胞的百分比较低(P<0.01),其Th细胞培养上清中IFN-γ的量也较低(P<0.01)。患者DC与同种异体的健康人Th细胞共培养,刺激Th1型细胞因子IFN-γ产生的能力低于正常人(P<0.01)。慢性乙肝患者体内DC功能的异常可能导致了外周血Th1细胞分化不足。     

Inhibition of human allergic T-helper type 2 immune responses by induced regulatory T cells requires the combination of interleukin-10-treated dendritic cells and transforming growth factor-β for their induction

BACKGROUND: In grass pollen-allergic individuals, T cell anergy can be induced by IL-10-treated dendritic cells (IL-10-DC) resulting in the suppression of T helper type 1 (Th1) as well as Th2 cells. This study was performed to analyse whether such IL-10-DC-treated T cells are able to act as regulatory T cells (Treg) suppressing the function of other T cells in the periphery. As transforming growth factor (TGF)-beta is also a potential inducer of Treg, we additionally analysed the inhibitory capacity of TGF-beta-treated T cells in this system. MATERIALS AND METHODS: Freshly isolated CD4+ or CD4+ CD25- T cells from grass pollen-allergic donors were stimulated with autologous mature monocyte-derived allergen-pulsed DC in the presence or absence of T cells previously cultured with IL-10-DC- and/or TGF-beta. RESULTS: Anergic T cells induced by allergen-pulsed IL-10-treated DC or allergen-pulsed DC and TGF-beta enhanced IL-10 production and strongly inhibited IFN-gamma production of freshly prepared peripheral CD4+ or CD4+ CD25- T cells while proliferation and Th2 cytokine production were only slightly reduced. The combination of allergen-pulsed IL-10-treated DC and TGF-beta had an additional effect leading to a significant suppression also of Th2 cytokine production and proliferation. Suppression was not antigen-specific and was mainly mediated by cell-to-cell contact and by the molecule-programmed death-1 and only partially by CTLA-4, TGF-beta and IL-10. CONCLUSION: These data demonstrate that regulatory T cells that also suppress Th2 cytokine production are induced by two signals: TGF-beta and IL-10-DC. This is of importance for the regulation of allergic immune responses and might be exploited for future therapeutic strategies for allergic diseases.     

Distinct subsets of human invariant NKT cells differentially regulate T helper responses via dendritic cells

Invariant natural killer T (iNKT) cells regulate the T helper (Th) 1/2 balance and elicit either enhancement or suppression of the immune responses. However, the exact mechanism by which iNKT cells exert these contrasting functions has remained elusive. We demonstrate herein that two major distinct subsets of human iNKT cells, CD4+CD8beta(-) (CD4+) and CD4(-)CD8beta(-) (double negative; DN) cells, express functional CD40 ligand (CD40L), but they differentially regulate the dendritic cell (DC) function by reciprocal NKT-DC interactions, thereby influencing the subsequent Th response. The CD4 subset stimulated by alpha-galactosylceramide (alpha-GalCer)-loaded DC immediately produced massive amounts of IL-4 and IL-13, which together with IFN-gamma enhanced CD40L-induced IL-12 production by DC. In contrast, the DN subset eliminated the DC by cytolysis and changed the living DC into a default subtype, in turn markedly down-regulating the levels of IL-12. Therefore, the DC stimulated by the CD4 subset preferentially induced Th1 responses, whereas the DC reacted with the DN subset induced a shift toward Th2 responses. These findings may provide an important insight into better understanding the contribution of iNKT-DC cross-talk governing the Th1/2 balance and the diverse influences of iNKT cells in various diseases.     

ST2 deletion enhances innate and acquired immunity to murine mammary carcinoma

ST2 is a member of the IL-1 receptor family and IL-33 was recently identified as its natural ligand. The IL-33/ST2 pathway regulates Th1/Th2 immune responses in autoimmune and inflammatory conditions, but the role of ST2 signaling in tumor growth and metastasis has not been investigated. We aimed to investigate whether ST2 gene deletion affects tumor appearance, growth, and metastasis, and antitumor immunity in an experimental metastatic breast cancer model. Deletion of ST2 in BALB/c mice bearing mammary carcinoma attenuated tumor growth and metastasis, which was accompanied by increased serum levels of IL-17, IFN-γ, and TNF-α and decreased IL-4. Tumor-bearing ST2-/- mice had significantly higher percentages of activated CD27high CD11bhigh NK cells, CD69+ and KLRG- NK cells and higher cytotoxic activity of splenocytes, NK cells, and CD8+ T cells in vitro. A significantly higher number of NK cells expressing IFN-γ were found in ST2-/- mice compared with WT recipients. In vivo depletion of CD8+ or NK cells revealed a key role for NK cells in enhanced antitumor immunity in ST2-/- mice. We report for the first time that suppressed breast cancer progression and metastasis in mice lacking ST2 corresponds mainly with enhanced cytotoxic activity of NK cells, and increased systemic Th1/Th17 cytokines.     

Ag-specific type 1 CD8 effector cells enhance methotrexate-mediated antitumor responses by modulating differentiated T cell localization, activation and chemokine production in established breast cancer

The chemotherapeutic agent methotrexate is widely used in the treatment of breast cancer. Although its mechanism-of-action has been defined, less is known about its interaction with T cell-mediated antitumor responses. Type 1 CD8 T cell-mediated immune responses (Tc1) are cytolytic, produce IFN-gamma and are associated with effective antitumor responses. Using a murine transgenic TCR tumor model, we show that single-dose treatment with methotrexate enhanced CD8-mediated type 1 antitumor responses when administered 3 days prior to Tc1 effector cell transfer. Co-treatment with methotrexate not only enhanced donor Tc1 cell accumulation and persistence at sites of primary tumor growth, but also promoted elevated levels of activated donor TIL cells. This markedly enhanced the appearance of endogenous differentiated (CD44^High) CD8 tumor-infiltrating cells when compared to that of corresponding groups receiving either MTX or Tc1 cell transfer alone. Such cells were acutely activated as defined by co-expression of surface markers associated with TCR engagement (CD69) and T cell activation (CD25) at both early (days 1–8) and late (days 12–20) stages following treatment. Conversely, such animals showed an early decrease in CD4⁺/CD44^High/CD25⁺/CD69⁺ T cells that correlated with delays in tumor growth in vivo. Moreover, cellular response kinetics appeared to further correlate with the up-regulation of endogenous T cells producing the chemokine IP-10 in vivo. This suggested that Tc1 cell transfer, in combination with chemotherapy, can enhance antitumor responses by modulating immunoregulatory T cells involved in homeostasis and immune tolerance within the tumor environment. These studies offer insight into mechanisms that enhance T cell-based immunotherapy in cancer.     

Th17/Treg及其相关细胞因子在结肠癌中的表达并与肿瘤分期的相关性

研究结肠癌患者肿瘤组织中Th17细胞、Treg细胞及患者外周血中相关细胞因子的表达水平,探讨其表达与肿瘤分期的相关性及可能机制。运用流式细胞分析(FACS)技术检测30例结肠癌肿瘤组织及癌旁正常组织中Th17细胞及Treg细胞的比例;采用逆转录聚合酶链反应技术(RT-PCR)检测20例结肠癌患者外周血中Th17、Treg相关细胞因子IL-23和IL-10的表达水平。结果显示结肠癌肿瘤组织中Th17细胞和Treg细胞的比例明显高于癌旁正常组织(P<0.05),进展期肿瘤组织中Treg细胞的比例高于早期(P<0.05),而Th17细胞的比例较早期无明显差异(P>0.05),进展期肿瘤组织中Th17/Treg细胞的比例比早期偏低(P<0.05)。结肠癌患者外周血中IL-23、IL-10的mRNA水平升高,与健康对照组差异明显(P<0.05),且进展期与早期结肠癌IL-10mRNA的表达水平差异显著(P<0.05),而IL-23mRNA在两组间无明显差异(P>0.05)。随着结肠癌病程的进展,肿瘤组织内Th17细胞及Treg细胞的比例逐渐升高,且Treg细胞比Th17细胞升高更加明显。相关细胞因子IL-23和IL-10在患者外周血中的变化趋势和Th17、Treg细胞在肿瘤组织中的变化趋势相一致,提示Th17、Treg细胞在结肠癌的表达可能与肿瘤免疫微环境中相关的细胞因子调节有关。     

Dendritic cells generated in the presence of GM-CSF plus IL-15 prime potent CD8+ Tc1 responses in vivo

Dendritic cells (DC) comprise a system of professional antigen-presenting cells, which induce the stimulation of very rare antigen-specific naive T cells. DC progenitors can be stimulated to differentiate into immature DC by various growth factors, including GM-CSF and IL-4. Here we show that IL-15, in combination with GM-CSF, is a growth factor for murine DC. Murine bone marrow cells, depleted of T cells, B cells, I-A+ cells and Gr-1+ granulocytes, and cultured in the presence of GM-CSF plus IL-15 (IL-15 DC), yielded DC expressing high levels of CD11c and MHC class II molecules, as well as CD11b. These cells expressed significant levels of CD40, CD80 and CD86, and could stimulate allogeneic CD4+ T cells efficiently. Interestingly, IL-15 DC were far superior to DC generated with GM-CSF plus IL-4 in stimulating allogeneic CD8+ T cells in vitro. Consistent with this, IL-15 DC induced much more potent antigen-specific CD8+ T cell responses with high levels of Th1 cytokines in vivo, compared to DC generated with GM-CSF plus IL-4, or with GM-CSF plus TGF-beta, or with GM-CSF alone. Together, these data suggest that IL-15 promotes the development of DC, which induce potent Th1 and Tc1 responses in vivo. This suggests potential roles for these IL-15 DC cells in the immunotherapy of tumors and infectious diseases.     

B7.2-Ig fusion proteins enhance IL-4-dependent differentiation of tumor-sensitized CD8+ cytotoxic T lymphocyte precursors

The B7/CD28 co-stimulatory pathway plays a critical role in T cell activation and differentiation. Our previous study demonstrated that administration of B7.2-Ig fusion proteins to tumor-bearing mice elicits IL-4-dependent, CD8+ T cell-mediated tumor regression. Here, we investigated whether B7.2-Ig stimulation of tumor-sensitized CD8+ CTL precursors during in vitro antigen re-sensitization actually results in their differentiation into mature CTLs and if so, whether such a process depends on IL-4 signals. Splenocytes from tumor-sensitized (tumor-bearing or tumor-immunized) mice exhibited low levels of anti-tumor CTL responses upon culturing alone, but induced strikingly enhanced CTL responses when stimulated in vitro with B7.2-Ig fusion proteins. Because CTLs were not generated from normal splenocytes even by B7.2-Ig stimulation, the expression of the B7.2-Ig effect required the in vivo tumor sensitization of CD8+ CTL precursors. Administration of anti-CD4 or anti-CD40 ligand (CD40L) to mice before tumor sensitization resulted in almost complete inhibition of CTL responses generated in the subsequent culture containing B7.2-Ig. In contrast, anti-IL-4 did not influence in vivo tumor sensitization required for CTL induction. However, B7.2-Ig stimulation of tumor-sensitized splenocytes enhanced IL-4 production and neutralization of this IL-4 with anti-IL-4 potently down-regulated CTL responses. These results indicate that B7.2-Ig enhances IL-4-dependent differentiation of anti-tumor CD8+ CTL precursors that can be sensitized in vivo depending on collaboration with CD4+ T cells involving CD40L function.     

Tumor-induced suppression of interferon-gamma production and enhancement of interleukin-10 production by natural killer (NK) cells: paralleled to CD4+ T cells

The predominance of type two cytokines in syngeneic B16 tumor-bearing mice was confirmed by analysing supernatant contents and mRNA copies of IFN-gamma, IL-4, IL-5, IL-10 and IL-13 from splenocytes. The cytokine-producing lymphocytes were then examined by double-staining flowcytometry. Both CD4+IFN-gamma+ T cells and DX5+IFN-gamma+ NK cells from spleen significantly declined, interestingly, the declining degrees of DX5+IFN-gamma+ NK cells were much greater than those of CD4+IFN-gamma+ T cells by the percentage in whole NK or T cells or the absolute amounts per spleen at early tumor stage (day 10) or tumor-advanced stage (day 20). In contrast to DX5+IFN-gamma+ NK cells, DX5+IL-10+ NK cells increased during tumor progression, the increasing degrees of DX5+IL-10+ NK cells were also much greater than those of CD4+IL-10+ T cells by the percentage or the absolute amounts. Though the percentage of DX5+IL-4+ NK cells only increased in early tumor stage (day 10), the increasing degree was also greater than that of CD4+IL-4+ T cells. In 20xfield view under laser confocal microscope, the mean numbers of DX5+IFN-gamma+ NK cells and CD4+IFN-gamma+ T cells dramatically declined after tumor inoculation. These results suggest that cytokines produced by NK cells, at least partly, account for the balance of type one and two cytokines as done by T cells, and in some conditions, that the NK1 or NK2 cells were possibly more sensitive to tumor progression.