CD4+CD25+ regulatory T cell-mediated changes in the expression of endocytic receptors and endocytosis process of human dendritic cells

CD4⁺CD25⁺ regulatory T cells (Tregs) are known to inhibit immune responses to antigens. Since, the process of antigen uptake by dendritic cells (DC) is central to induction of immune responses, we analyzed the effect of Tregs on the expression of endocytic receptors on DC and its repercussion on antigen uptake. Our results demonstrate that Tregs down-regulate the expression and uptake of antigens via C-type lectin-like receptors CD206 and DC-SIGN, restrain the pinocytosis process of DC and augment the expression of FcγRIIB, an inhibitory Fcγ receptor the engagement of which by IgG-bound antigens leads to inhibition of DC activation. Our results thus provide an additional insight on the pertinence of strategies aimed at blocking Treg functions towards improved vaccination protocols.     

CD4+ and CD8+ mediated cellular immune response to recombinant influenza nucleoprotein

The stimulatory properties of soluble recombinant influenza nucleoprotein (NP) on purified CD4(+) and CD8(+) T cells from young and elderly individuals were studied. Recombinant influenza NP failed to induce proliferation of resting CD4(+) and CD8(+) T cells in the absence of IL-2. Addition of small amounts of IL-2, however, led to strong proliferation of resting CD4(+) and CD8(+) T cells from young and elderly donors. NP-reactive CD4(+) and CD8(+) T cell lines from both age groups grew equally well under long-term culture conditions. T cell lines raised to live influenza virus could recognize recombinant influenza NP and showed a substantial proliferative response. Stimulation of CD8(+) T cells is presumably due to cross-presentation, as EBV-transformed MHC class I-positive cell lines, which are incapable of antigen processing, stimulated live influenza virus-reactive CD8(+) T cell lines when loaded with NP-derived immunodominant peptides but not following loading with the whole NP molecule. Vaccines containing recombinant influenza NP might confer cross-protective immunity and could therefore be especially useful in cases of major epidemics or pandemics.     

Energy-restricted diets result in higher numbers of CD4, CD8, immunoglobulins (A, M, and G), and CD45RA cells in spleen and CD4, immunoglobulin A, and CD45RA cells in colonic lamina propria of rats

Dietary energy restriction (ER) offers certain health benefits, particularly when ER is controlled through manipulation of dietary fats. Our hypothesis is that cellular immunity is modulated by dietary ER. Furthermore, we believe that the immune response may differ between spleen and colon because their lymphatic and vascular organization is different. The objective of the study was to test this hypothesis by determining the effects of dietary ER through manipulation of energy intake from high-fat (HF) diets on the expression and frequency of the CD4⁺ (T-helper/T-inducer) and CD8⁺ (T-cytotoxic/T-suppressor) cells, CD45RA (B-cell–specific marker), and immunoglobulins (Ig) A-, G-, and M-bearing cells in spleen and colon in rats by immunohistochemical method. Rats fed the HF diet had a significantly (P < .05) reduced number of immune cells as compared with those fed ER diets. Energy-restricted diet–fed rats showed higher (P < .05) numbers of CD4⁺, CD8⁺, IgA, IgM, IgG, and CD45RA cells in spleen and CD4⁺, IgA, and CD45RA cells in colonic lamina propria. The IgA-containing cells were markedly higher in the colon compared with the spleen. No change occurred in the number of IgM- and IgG-containing cells in colonic tissues between groups, except for the 20% ER group where IgM-labeled cells were higher (P < .05) compared with HF and 40% ER groups. These findings suggest that ER may modulate adaptive immune function and that CD4⁺ and IgA cells may serve as biological indicators for dietary energy-modulated immunoresponse in spleen and colon, respectively.     

CD207 cells recruitment to the vaccination site and draining lymph nodes after the administration of DC-Apo/Nec vaccine in mice

De novo ectopic lymphoid tissue formation is known to occur in certain disease and inflammatory settings. After an effective vaccination with dendritic cells (DC) charged with melanoma apoptotic/necrotic cells (Apo/Nec), a subcutaneous tertiary lymphoid structure was organized, where retained vaccine cells interacted with recruited inflammatory and T cells. In this work we report for the first time the recruitment of two morphologically different CD207⁺ cells to vaccination site. The time-course behavior of CD207⁺ cells was reciprocal between vaccination site and draining lymph nodes (DLNs). After 6–10 days, CD207⁺ cells localized at the paracortical region of DLNs, in close contact with T cell population. DLNs were enriched in a peculiar MHCII⁺ CD11c⁽⁻⁾ CD207⁺ population, whose role remains to be determined. Whether CD207⁺ cells migration to the vaccination site can be associated with a differential anti-tumoral response remains as an open and exciting question.     

Profound CD8+ T cell immunity elicited by sequential daily immunization with exogenous antigen plus the TLR3 agonist poly(I:C)

The development of vaccines that elicit robust CD8⁺ T cell immunity has long been a subject of intense investigation. Although whole exogenous protein has not historically been considered as useful for eliciting CD8⁺ T cell immunity, we report herein that whole, protein antigen is capable of eliciting profound levels of CD8⁺ T cell immunity if it is administered via repeated, daily subcutaneous immunization in combination with the TLR3 agonist poly(I:C). Mice immunized for four consecutive days with 100 μg of either whole exogenous OVA or whole HPV16 E7 protein combined with 10 μg of poly(I:C) mounted remarkable antigen-specific CD8⁺ T cell responses as measured by tetramer staining and ELISPOT analysis of splenocytes and peripheral blood, with up to 30% of peripheral CD8⁺ T cells being antigen specific within 7-8 days of vaccination. CD8⁺ T cell immunity elicited using this vaccination approach was critically dependent upon cross presentation, as either whole protein or long synthetic peptides were highly effective immunogens whereas minimal peptide epitopes were not. Vaccine-induced CD8⁺ T cells were also able to regress large, established tumors in vivo. Together these data suggest that ‘cluster’ vaccination with exogenous antigen combined with TLR3 agonist may constitute a profoundly important advancement in therapeutic vaccine design.     

Frequencies of CD4+ T Regulatory Cells and their CD25high and FoxP3high Subsets Augment in Peripheral Blood of Patients with Acute and Chronic Brucellosis

Objectives

Brucellosis remains one of the most common zoonotic diseases worldwide. In humans, brucellosis can be a serious, debilitating, and sometimes chronic disease. Different mechanisms can be postulated as to the basis for the induction of the chronic status of infectious diseases that T regulatory cells are one of the most important related mechanisms. The current study was designed to determine whether percentage of CD4+Treg cells and their CD25^high and FoxP3^high subpopulations in peripheral blood are changed in human brucellosis samples in comparison to a control group.

Methods

In total, 68 brucellosis patients (acute form: n = 43, chronic form: n = 25) and 36 healthy volunteers entered our study. After isolating of peripheral blood mononuclear cells, heparinized venous blood samples were obtained from both patients and healthy donors, CD4, CD25, and FoxP3 molecules were evaluated by two- and three-color flow cytometric methods.

Results

The results revealed a new finding in relation to Treg cells and human brucellosis. The numbers of CD4⁺Treg cells and their CD25^high and FoxP3^high subsets increase significantly in the peripheral blood of acute and chronic forms of brucellosis samples compared with healthy groups, with this increase being greater in the chronic group.

Conclusion

There seems to be a correlation between increase of CD4+Treg cells and their subsets and the disease progress from healthy state to acute and chronic brucellosis.     

Mucosal immunization in macaques upregulates the innate APOBEC 3G anti-viral factor in CD4 memory T cells

APOBEC3G is an innate intracellular anti-viral factor which deaminates retroviral cytidine to uridine. In vivo studies of APOBEC3G (A3G) were carried out in rhesus macaques, following mucosal immunization with SIV antigens and CCR5 peptides, linked to the 70 kDa heat shock protein. A progressive increase in A3G mRNA was elicited in PBMC after each immunization (p < 0.0002 to p ≤ 0.02), which was maintained for at least 17 weeks. Analysis of memory T cells showed a significant increase in A3G mRNA and protein in CD4⁺CCR5⁺ memory T cells in circulating (p = 0.0001), splenic (p = 0.0001), iliac lymph nodes (p = 0.002) and rectal (p = 0.01) cells of the immunized compared with unimmunized macaques. Mucosal challenge with SIVmac 251 showed a significant increase in A3G mRNA in the CD4⁺CCR5⁺ circulating cells (p < 0.01) and the draining iliac lymph node cells (p < 0.05) in the immunized uninfected macaques, consistent with a protective effect exerted by A3G. The results suggest that mucosal immunization in a non-human primate can induce features of a memory response to an innate anti-viral factor in CCR5⁺CD4⁺ memory and CD4⁺CD95⁺CCR7⁻ effector memory T cells.     

A novel in vitro survival assay of small intestinal stem cells after exposure to ionizing radiation

The microcolony assay developed by Withers and Elkind has been a gold standard to assess the surviving fraction of small intestinal stem cells after exposure to high (≥8 Gy) doses of ionizing radiation (IR), but is not applicable in cases of exposure to lower doses. Here, we developed a novel in vitro assay that enables assessment of the surviving fraction of small intestinal stem cells after exposure to lower IR doses. The assay includes in vitro culture of small intestinal stem cells, which allows the stem cells to develop into epithelial organoids containing all four differentiated cell types of the small intestine. We used Lgr5-EGFP-IRES-CreERT2/ROSA26-tdTomato mice to identify Lgr5⁺ stem cells and their progeny. Enzymatically dissociated single crypt cells from the duodenum and jejunum of mice were irradiated with 7.25, 29, 101, 304, 1000, 2000 and 4000 mGy of X-rays immediately after plating, and the number of organoids was counted on Day 12. Organoid-forming efficiency of irradiated cells relative to that of unirradiated controls was defined as the surviving fraction of stem cells. We observed a significant decrease in the surviving fraction of stem cells at ≥1000 mGy. Moreover, fluorescence-activated cell sorting analyses and passage of the organoids revealed that proliferation of stem cells surviving IR is significantly potentiated. Together, the present study demonstrates that the in vitro assay is useful for quantitatively assessing the surviving fraction of small intestinal stem cells after exposure to lower doses of IR as compared with previous examinations using the microcolony assay.     

不同CD4+T淋巴细胞水平的HIV感染者乙型肝炎疫苗免疫效果及持久性研究

目的 分析HIV感染者CD4⁺T淋巴细胞（CD4）水平对乙肝疫苗免疫应答的影响,探讨不同CD4水平的HIV感染者乙肝疫苗免疫效果及其持久性,为优化HIV感染者乙肝疫苗免疫策略提供理论支持。方法 以2014年广西壮族自治区CDC和宁明县CDC管理的参加0-1-6月20μg和60μg乙肝疫苗接种随机对照试验的182名HIV感染者为研究对象,在首针接种后6个月和全程接种后1个月、6个月、1年和3年时,采集研究对象静脉血5 ml,并采用化学发光微粒子免疫分析方法定量检测乙肝表面抗体（抗-HBs）。本研究在既往研究基础上,着重分析不同CD4水平下乙肝疫苗接种后的免疫效果及持久性。结果 CD4<350个/μl的HIV感染者乙肝疫苗全程接种后1个月时,抗-HBs几何平均浓度（GMC）为442.50 mIU/ml,抗-HBs阳性率为71.05%（27/38）,强阳性率为44.74%（17/38）,明显低于CD4 ≥ 350个/μl者[583.90 mIU/ml、92.13%（117/127）和77.95%（99/127）]（P<0.05）;多因素分析结果显示,控制混杂因素后,CD4<350个/μl者乙肝疫苗抗-HBs阳性的概率是CD4 ≥ 350个/μl者的0.14倍（95% CI：0.03~0.62）,CD4水平较低是乙肝疫苗无应答的危险因素。全程接种后6个月到3年时,CD4<350个/μl者抗-HBs GMC（195.00~27.55 mIU/ml比300.10~45.81 mIU/ml）、阳性率（56.67%~36.67%比78.57%~51.58%）和强阳性率（33.33%~6.67%比44.64%~15.79%）不同程度下降,且均低于CD4 ≥ 350个/μl者。结论 CD4<350个/μl的HIV感染者乙肝疫苗无应答风险高,免疫持久性较差,应定期监测HIV感染者抗-HBs水平,并特别关注CD4<350个/μl者,抗-HBs阴性时应尽早全程及加强接种乙肝疫苗。     

Oxidative stress due to radiation in CD34+ Hematopoietic progenitor cells: protection by IGF-1

Radiation exerts direct as well as indirect effects on DNA through the generation of reactive oxygen species (ROS). Irradiated hematopoietic progenitor cells (HPCs) experience DNA strand breaks, favoring genetic instability, due to ROS generation. Our aim was to study the effect of a range of radiation doses in HPCs and the possible protective mechanisms activated by insulin-like growth factor-1 (IGF-1). ROS generation was evaluated, in the presence or absence of IGF-1 in liquid cultures of human HPCs-CD34⁺ irradiated with 1-, 2- and 5-Gy X-rays, using a flow cytometry assay. Manganese superoxide dismutase (MnSOD) expression was studied by western blot analysis and visualized by an immunofluorescence assay. Apoptosis was estimated using the following assays: Annexin-V assay, DNA degradation assay, BCL-2/BAX mRNA and protein levels and caspase-9 protein immunofluorescence visualization. Viability and clonogenic potential were studied in irradiated HPCs. The generation of superoxide anion radicals at an early and a late time point was increased, while the hydrogen peroxide generation at a late time point was stable. IGF-1 presence further enhanced the radiation-induced increase of MnSOD at 24 h post irradiation. IGF-1 inhibited the mitochondria-mediated pathway of apoptosis by regulating the m-RNA and protein expression of BAX, BCL-2 and the BCL-2/BAX ratio and by decreasing caspase-9 protein expression. IGF-1 presence in culture media of irradiated cells restored the clonogenic capacity and the viability of HPCs as well. In conclusion, IGF-1 protects HPCs-CD34⁺ from radiation effects, by eliminating the oxidative microenvironment through the enhancement of MnSOD activation and by regulating the mitochondria-mediated pathway of apoptosis.     

人肺腺癌肿瘤细胞免疫表型CD133、CD34、CD44的实验研究

目的 拟验证CD133、CD34、CD44作为人肺腺癌肿瘤干细胞表面标记物的合理性.方法 采集新鲜肺腺癌组织标本,利用两种体外培养方法扩增出贴壁细胞和悬浮细胞球两种肿瘤细胞,采用免疫荧光检测比较CD133、CD34和CD44在两种培养细胞中表达的差异.结果 悬浮球肿瘤细胞培养较贴壁肿瘤细胞生长速度慢、维持时间长且成功率高(72.5% vs 47.5%,P＜0.05).CD133、CD34和CD44在悬浮细胞球中表达率和表达量明显高于贴壁肿瘤细胞(68.97%,82.76%,93.10% vs 5.26%,15.79%,5.26%,P＜0.01).结论 CD133、CD34和CD44可能作为分离人肺腺癌肿瘤干细胞的表面蛋白表标记组合.

Abstract：

Objective To validate the possibility of CD133 CD34 CD44 be served as biomarkers in cancer stem cell of human lung adenocarcinoma. Methods Two kinds of culturing methods were performed to generate adhesive tumor cells and floating aggregates, and the differences of expression of CD133 CD34 CD44 between 2 kinds of cultured cells were observed by immunofluorescence. Results Floating aggregates grew more slowly, kept activity for longer period than adhesive cells (72.5% vs 47.5%,P＜0.05). Floating aggregates expressed higher level of CD133, CD34 and CD44 than adhesive cells (68.97%,82.76%,93.10% vs 5.26%,15.79%,5.26%,P＜0.01). Conclusions The combination of CD133, CD34 and CD44 probably can be used as surface markers of cancer stem cells for human lung adenocarcinoma.     

Immunization with the Leishmania infantum recombinant cyclophilin protein 1 confers partial protection to subsequent parasite infection and generates specific memory T cells

Control of zoonotic visceral leishmaniosis can be achieved using several available drugs. These drugs present high toxicity and require longer treatment regimens which complicate compliance to the treatment. Other control measures directed to the vector or the reservoirs are useful tools to restrain the spreading of this disease but the effects are transitory. A safe, affordable and efficient vaccine conferring long lasting immunity should be the most cost effective way of controlling zoonotic visceral leishmaniosis. The present study aims at characterizing a cyclophilin protein 1 of Leishmania infantum (LiCyP1) and investigating whether recombinant LiCyP1 (LirCyP1) is able to confer protection against infection by evaluating viable parasite load and the generation of specific CD4⁺ and CD8⁺ effector and central memory T cells in rodent model. LiCyP1 is present in the cytoplasm of L. infantum amastigotes and promastigotes. Immunization of BALB/c mice with LirCyP1 confers high protection to L. infantum infection, causing a marked reduction in parasite replication in the liver and spleen. Furthermore, helper and cytotoxic memory T cell subsets able to specifically recognize parasite antigens expanded in immunized and in challenged mice. CD4⁺ T cell subpopulation of intermediate phenotype (CD62L^highCD127^low) of challenging mice also presented an accentuated expansion after the recall. This study demonstrated that LirCyP1 confers partial protection to L. infantum infection, promoting the generation of a desired long lasting immunity. LirCyP1 can be considered a potential candidate for the design of a vaccine against zoonotic visceral leishmaniosis.     

人肺腺癌肿瘤细胞免疫表型CDl33、CD34、CD44的实验研究

目的拟验证CDl33、CD34、CD44作为人肺腺癌肿瘤干细胞表面标记物的合理性。方法采集新鲜肺腺癌组织标本,利用两种体外培养方法扩增出贴壁细胞和悬浮细胞球两种肿瘤细胞,采用免疫荧光检测比较CDl33、CD34和CD44在两种培养细胞中表达的差异。结果悬浮球肿瘤细胞培养较贴壁肿瘤细胞生长速度慢、维持时间长且成功率高（72．5％VS47．5％,P〈0．05）。CDl33、CD34和CD44在悬浮细胞球中表达率和表达量明显高于贴壁肿瘤细胞（68．97％,82．76％,93．10％VS5．26％,15．79％,5．26％,P〈0．01）。结论CDl33、CD34和CD44可能作为分离人肺腺癌肿瘤干细胞的表面蛋白表标记组合。     

Actively induced antigen-specific CD8(+) T cells by epitope-bearing parasite pre-infection but not prime/boost virus vector vaccination could ameliorate the course of Plasmodium yoelii blood-stage infection

The lack of MHC molecules on red blood cells (RBCs) has led to questions regarding the immunological function of CD8(+) T cells against malarial blood-stage (MBS). However, several recent reports contradicting with this concept have suggested that they play an important role in the course of MBS infection. The present study generated genetically engineered murine malaria, Plasmodium yoelii, which expresses a well-defined Trypanosoma cruzi-derived, H-2K(b)-restricted CD8(+) T cell epitope, ANYNFTLV. Prime/boost vaccination by the use of recombinant adenovirus and recombinant modified vaccinia virus Ankara (MVA), which induced an enhanced number of ANYNFTLV-specific CD8(+) T cells, failed to prevent a pathological outcome to occur upon ANYNFTLV-expressing murine MBS infection. This outcome did not change even with the combination of passive transfer of an appreciable number of in vitro-expanded ANYNFTLV-specific CD8(+) T cells. In contrast, the pre-infection of mice with T. cruzi, which intrinsically bears the same CD8(+) T cell epitope significantly improved the survival of ANYNFTLV-expressing malaria-infected mice but not that of control malaria-infected ones. This protective effect was abrogated by the use of a CD8(+) T cell-depleting monoclonal antibody. Although the protective effect was observed only in certain situations, the actively induced antigen-specific CD8(+) T cells could ameliorate the pathologies caused by the MBS. This is the first study to implicate that the active induction of antigen-specific CD8(+) T cells should be included in the development of a vaccine against MBS.     

Effects of Vitamin D Supplementation on CD4+ T Cell Subsets and mTOR Signaling Pathway in High-Fat-Diet-Induced Obese Mice

Obesity is associated with an impaired balance of CD4⁺ T cell subsets. Both vitamin D and obesity have been reported to affect the mTOR pathway. In this study, we investigated the effects of vitamin D on CD4⁺ T cell subsets and the mTOR pathway. Ten-week-old male C57BL/6 mice were divided into four groups and fed diets with different fat (control or high-fat diets: CON or HFD) and vitamin D contents (vitamin D control or supplemented diets: vDC or vDS) for 12 weeks. T cells purified by negative selection were stimulated with anti-CD3/anti-CD28 mAbs and cultured for 48 h. The percentage of CD4⁺IL-17⁺ T cells was higher in the vDS than vDC groups. The CD4⁺CD25⁺Foxp3⁺ T cells percentage was higher in HFD than CON groups. The phospho-p70S6K/total-p70S6K ratio was lower in vDS than vDC, but the phospho-AKT/total-AKT ratio was higher in vDS than vDC groups. Hif1α mRNA levels were lower in vDS than vDC groups. These findings suggest HIF1α plays an important role in vitamin-D-mediated regulation of glucose metabolism in T cells, and dietary vitamin D supplementation may contribute to the maintenance of immune homeostasis by regulating the mTOR pathway in T cells.     

Memory CD8 T cells elicited by HIV-1 lipopeptide vaccines display similar phenotypic profiles but differences in term of magnitude and multifunctionality compared with FLU- or EBV-specific memory T cells in humans

Differentiation marker, multifunctionality and magnitude analyses of specific-CD8⁺ memory T cells are crucial to improve development of HIV vaccines designed to generate cell-mediated immunity. Therefore, we fully characterized the HIV-specific CD8⁺ T cell responses induced in volunteers vaccinated with HIV lipopeptide vaccines for phenotypic markers, tetramer staining, cytokine secretion, and cytotoxic activities. The frequency of ex vivo CD8⁺ T cells elicited by lipopeptide vaccines is very rare and central-memory phenotype and functions of these cells were been shown to be important in AIDS immunity. So, we expanded them using specific peptides to compare the memory T cell responses induced in volunteers by HIV vaccines with responses to influenza (FLU) or Epstein Barr virus (EBV). By analyzing the differentiation state of IFN-γ-secreting CD8⁺ T cells, we found a CCR7⁻CD45RA⁻CD28^+int/CD28⁻ profile (>85%) belonging to a subset of intermediate-differentiated effector T cells for HIV, FLU, and EBV. We then assessed the quality of the response by measuring various T cell functions. The percentage of single IFN-γ T cell producers in response to HIV was 62% of the total of secreting T cells compared with 35% for FLU and EBV, dual and triple (IFN-γ/IL-2/CD107a) T cell producers could also be detected but at lower levels (8% compared with 37%). Finally, HIV-specific T cells secreted IFN-γ and TNF-α, but not the dual combination like FLU- and EBV-specific T cells. Thus, we found that the functional profile and magnitude of expanded HIV-specific CD8⁺ T precursors were more limited than those of to FLU- and EBV-specific CD8⁺ T cells. These data show that CD8⁺ T cells induced by these HIV vaccines have a similar differentiation profile to FLU and EBV CD8⁺ T cells, but that the vaccine potency to induce multifunctional T cells needs to be increased in order to improve vaccination strategies.