Inhibition of microRNA-17-5p reduces the inflammation and lipid accumulation,and up-regulates ATP-binding cassette transporterA1 in atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory disease of the arterial wall. Macrophages are considered to be closely associated with the development and progression of AS. However, the precise mechanism of miR-17-5p in the macrophages under AS remains incompletely clarified. This study investigated the regulatory effect of miR-17-5p on the inflammation and lipid accumulation in mouse macrophages both in vivo and in vitro. It was found that miR-17-5p was highly expressed with lowered ATP-binding cassette transporterA1 (ABCA1) level in the peripheral blood leucocytes (PBLs) of AS patients. Moreover, the level of miR-17-5p was up-regulated in the macrophages of ApoE^?/? mice fed with a high-cholesterol diet. Furthermore, we injected miR-17-5p antagomir into AS mice or transfected miR-17-5p inhibitors into mouse macrophage RAW264.7 cells. Results showed that downregulation of miR-17-5p significantly reduced the production of inflammatory cytokines, inhibited the lipid accumulation and up-regulated ABCA1, and activated peroxisome proliferator-activated receptor (PPAR) γ/Liver X receptor (LXR) α signaling pathway. Additionally, ABCA1 was found to be a target of miR-17-5p by directly binding to 3′-untranslated region (3′-UTR) of its mRNA. Our study indicates a novel regulatory mechanism for miR-17-5p by interacting with ABCA1, which could be a therapy-target for the treatment of AS.     

Inhibition of a secondary human alloimmune response via the soluble active component of CD154 (CD40L) in severe combined immune-deficient mice engrafted with human lymphocytes

BACKGROUND: Alloimmunization requires a process known as co-stimulation. An important co-stimulatory pathway for most immune responses is mediated by the interaction of CD40 on antigen-presenting cells with CD154 (CD40L) on host T cells. Blockade of this co-stimulatory pathway simultaneous with exposure to challenge with HLA-incompatible cells is hypothesized to inhibit alloimmunization. STUDY DESIGN AND METHODS: Severe combined immune-deficient (SCID) mice were reconstituted with human peripheral blood lymphocytes (Hu-PBL-SCID mice) from a subject primed to HLA antigens and challenged with HLA-incompatible lymphocytes. Mice were challenged in the presence or absence of an 18-kDa soluble recombinant active form of human CD154 (18-kDa CD154). Human IgG production, alloimmunization, and in vitro T-cell responsiveness were assessed. RESULTS: There was no significant effect of 18-kDa CD154 on human IgG levels in these mice, but it inhibited the development of HLA-specific alloantibody in this model to five subsequent untreated white cell challenges. In vitro T-cell proliferation in a mixed lymphocyte culture was also prevented by 18-kDa CD154. CONCLUSION: The recombinant protein 18-kDa CD154 inhibited the ability of the Hu-PBL-SCID mice to mount a secondary immune response to allostimulation. This implies that transfusion-induced alloimmunization utilizes CD40-CD154 co-stimulation and that blockade of this pathway can inhibit T-cell function and interfere with the development of alloimmunization.     

Reshaping of T-lymphocyte compartment in adult prepubertaly ovariectomised rats: A putative role for progesterone deficiency

This study explores the role of ovarian hormones in the phenotypic shaping of peripheral T-cell pool over the reproductive lifespan of rats. For this purpose, 2-month-old prepubertally ovariectomised (Ox) rats, showing oestrogen and progesterone deficiency, and 11-month-old Ox rats, exhibiting only progesterone deficiency, were examined for thymus output, and cellularity and composition of major TCRαβ+ peripheral blood lymphocyte (PBL) and splenocyte subsets. Although ovariectomy increased thymic output in both 2- and 11-month-old rats, the count of both CD4+ and CD8+ PBLs and splenocytes increased only in the former. In the blood and spleen of 11-month-old Ox rats only the count of CD8+ cells increased. Although ovariectomy affected the total CD4+ count in none of the examined compartments from the 11-month-old rats, it increased CD4+FoxP3+ PBL and splenocyte relative proportions over those in the age-matched controls. The age-related differences in the cellularity and the major subset composition in Ox rats were linked to the differences in the ovarian steroid hormone levels registered in 2- and 11-month-old rats. The administration of progesterone to Ox rats during the seven days before the sacrificing confirmed contribution of this hormone deficiency to the ovariectomy-induced changes in the TCRαβ+ PBL and splenocyte pool from 11-month-old rats. The expansion of the CD8+ splenocyte subset in the 11-month-old Ox rats reflected increases in cellularity of memory and, particularly, naïve cells. This was due to greater thymic output of CD8+ cells and homeostatic proliferation than apoptosis in 11-month-old Ox rats when compared with age-matched sham-Ox control rats. The homeostatic changes within CD8+ splenocyte pool from 11-month-old Ox rats, most likely, reflected the enhanced splenic IL-7 and TGF-β mRNA expression. Overall, in adult female rats, circulating oestrogen and progesterone provide maintenance of T-cell counts, a diversity of T-cell repertoire, and the main T-cell subset composition in the periphery. Progesterone deficiency affects mainly the CD8+ lymphocyte compartment through increasing thymic CD8+ cell export and upsetting homeostatic regulation within the CD8+ splenocyte pool. These alterations were reversible through progesterone supplementation.     

Survival of bone marrow-derived mesenchymal stem cells in a xenotransplantation model.

Mesenchymal stem cells (MSCs) are immunoprivileged and the allogeneic MSCs implantation has been used to facilitate tissue repairs such as bone and cartilage defect. The present study aimed to investigate the feasibility of xenogeneic MSCs implantation. Green fluorescent protein (GFP) transgenic rat bone marrow-derived MSCs were loaded into HA/TCP Skelite blocks and implanted intramuscularly into the quadriceps of the MF1 and SCID mice. After 11 weeks, the implants were harvested and processed for further examinations. The peripheral blood mononuclear cells of each animal were also collected to measure the in vitro immune responses using mixed lymphocyte culture and cytotoxic assay. In the MF1 mice, some surviving MSCs were found in the explants after 11 weeks of implantation, but there was no sign of new bone formation as neither osteocalcin mRNA nor osteoid tissues were detected in the explants; the lymphocyte proliferation and cytotoxicity against donor MSCs were significantly increased in the animals with the xenogeneic MSCs implantation compared with the control littermates without transplantation. In the control SCID mice, osteoid tissues derived from the implanted MSCs were found in the explants; no difference of lymphocyte proliferation and cytotoxicity against the donor MSCs was detected between the SCID mice with or without MSCs implantation. The data suggested that rat MSCs survived the 11 weeks of xenotransplantation in the MF1 mice, but the increased host immune sensitization led to the impaired in vivo osteogenesis potential of MSCs.     

Antibody producing human-human hybridomas. I. Technical aspects

Technical aspects of generation of antibody-secreting human-human hybridomas are evaluated as based on 100 human-human fusions with a human B-lymphoma cell line (RH-L4) or the SKO-007 myeloma cell line as malignant fusion partners, and compared with similar fusion conditions in the mouse hybridoma system. The yield of hybrids was significantly lower when normal peripheral blood lymphocytes were used as fusion partners as compared with spleen lymphocytes, but could be substantially improved by increasing the amount of mitotic active B-lymphocytes by mitogen stimulation of the lymphocytes, preferably in HAT medium, prior to fusion. Furthermore, human hybrids grew slower and had a higher degree of chromosomal instability than usually observed in the mouse hybridoma system. Thus, out of 72 fusions, only 3 stable hybrids with antibody production against a predefined antigen were established. The importance of improved sources of human B-lymphocytes for human-human hybridoma production is discussed and methods of obtaining such improvement suggested.     

胃泌素拮抗剂和活化T淋巴细胞联合应用对结肠癌细胞的杀伤作用

目的:探讨联合应用胃泌素拮抗剂和CD28/CD80单克隆抗体共刺激活化的健康人外周血T淋巴细胞(PBLs)在体外对结肠癌细胞株HT-29的杀伤作用.方法:分离与体外培养外周血PBLs,并用CD28/CD80共刺激活化PBLs;用含活化的PBLs和(或)胃泌素拮抗剂CI-988的RPMI 1640培养基培养HT-29细胞.MTT法检测2者对HT-29细胞的杀伤率,并用电镜观察效应细胞杀伤结肠癌细胞株HT-29的超微结构及HT-29细胞的凋亡情况.结果:胃泌素拮抗剂与活化PBLs合用,对结肠癌细胞株HT-29的杀伤率((95.81±1.99)%)大于单用胃泌素拮抗剂((66.36±1.31)%)(P＜0.05).电镜结果显示,效应细胞作用12 h肿瘤细胞就发生部分坏死,部分肿瘤细胞可见凋亡.结论:联合应用活化的PBLs和胃泌素拮抗剂CI-988可以提高对结肠癌细胞株HT-29 杀伤作用.活化的淋巴细胞杀伤结肠癌细胞可能是通过诱导肿瘤细胞坏死及凋亡2条途径来实现.     

Improving the immunogenicity and protective efficacy of the EtMIC2 protein against Eimeria tenella infection through random mutagenesis

In recent years, directed evolution has emerged as an efficient tool to develop and identify novel protein variants. Eimeria tenella microneme-2 (EtMIC2) is a promising vaccine candidate for use against E. tenella infection; however, it only yields partial protection. The present study aimed to improve the immunogenicity and protective efficacy of EtMIC2 through random mutagenesis. Mutagenesis gene libraries of EtMIC2 were generated using error-prone polymerase chain reaction (epPCR), and the corresponding variant proteins were displayed on the yeast cell surface. Variant EtMIC2 proteins with high immunogenicity were screened through fluorescence-activated cell sorting (FACS) based on the affinity between polyclonal antibodies and antigens. Seven effective variant proteins were screened out and heterogeneously expressed in Escherichia coli as subunit vaccines. The protective efficacy of the variant proteins against E. tenella infections was then evaluated in chicken. Two variant proteins (1130 and 2119) displayed higher immunogenicity and protective efficacy than the wild-type EtMIC2 protein against E. tenella infections, increasing body weight gains and significantly decreasing lesion scores and fecal oocyst shedding, and increasing sIgA antibody production and lymphocyte proliferation. These variants displayed potential for use in the development of subunit vaccines for coccidiosis in chickens. The present results also indicate that directed evolution technology is useful for improving the immunogenicity and protective efficacy of parasite antigens.     

CpGODN结合CD28/CD80单抗活化T细胞对结肠癌细胞的杀伤作用

目的研究联合应用CpGODN和CD28/CD80单抗共刺激健康人外周血T淋巴细胞(PBLs)在体外对结肠癌细胞株HT-29的杀伤作用,为结直肠癌的过继免疫治疗可能性提供参考。方法PBLs的分离与体外培养;CD28/CD80共刺激活化PBLs;用含共刺激活化PBMC或/和CpGODN的100ml/L胎牛血清的RPMI1640培养基培养细胞,测生长曲线。MTT法检测活化细胞的体外淋巴细胞毒作用,并用电镜观察效应细胞杀伤的结肠癌细胞超微结构及用流式细胞仪检测结肠癌细胞的相关凋亡情况。结果CpGODN本身对HT-29细胞有一定的杀伤作用(P<0.05),CD28/CD80共刺激活化PBLs在体外对结肠癌细胞株HT-29杀伤作用明显(P<0.01),CpGODN与CD28/CD80共刺激活化PBLs合用,对HT-29的杀伤作用显著大于CpGODN单独对HT-29细胞杀伤作用(抑制率92.31%vs68.00%,P<0.01),亦大于单独应用CD28/CD80共刺激活化PBMC对HT-29细胞的杀伤作用(P<0.05),CpGODN增加了HT-29细胞对共刺激活化PBMC的敏感性。电镜结果显示,效应细胞作用24h肿瘤细胞就部分发生坏死,部分肿瘤细胞可见凋亡。流式细胞仪检测效应细胞HT-29细胞72h明显凋亡。结论联合应用CpGODN可以提高单抗协同诱导的效应细胞对结肠癌细胞株HT-29杀伤作用,而坏死细胞进一步增多说明效应细胞是通过诱导肿瘤细胞坏死及细胞凋亡两条途径来实现抑制杀伤作用从而说明活化的淋巴细胞杀伤结肠癌细胞是通过坏死及凋亡实现的。     

广西瑶、侗、苗、壮等民族外周血白细胞中BK病毒的研究

目的了解广西瑶、侗、苗、壮等少数民族外周血白细胞中多瘤病毒BKV的感染情况，掌握该区人群BKV的携带情况，阐明BKV在人体内的传播方式。方法于2006年1月-2008年5月采集广西瑶、侗、苗、壮等少数民族及汉族健康人外周血标本各2500份，提取淋巴细胞基因组DNA，用巢式PCR方法扩增BKV的保守区编码序列，统计分析不同少数民族、年龄、性别组BKV—DNA检出率。结果2500份健康人外周血白细胞（PBLs）样品中BKV—DNA序列检出率为60．6％，不同民族、性别、年龄组之间无显著性差异（P〉0．05）。结论BKV在广西瑶、侗、苗、壮等少数民族及汉族健康人PBLs中存在较高的感染率，本研究证实了PBLs是BKV在体内的潜伏细胞及传播载体，应加强对BKV条件致病性的认识，积极防治、减少BKV相关性肾病（BKVN）的发生率。     

Evidence for a modulatory effect of IL-10 on both Th1 and Th2 cytokine production: the role of the environment

Allergic and other immune-mediated diseases are complex disease states determined by interplay between host genetics and environmental factors. Environmental changes such as fewer infections and reduced exposure to microbial products have been suggested to have led to insufficient regulation of Th1 and Th2 immune responses, causing an increased incidence of inflammatory diseases. The objective of the present study was to investigate the effect of poor living environmental conditions on mitogen-induced production of cytokines (Th1 and Th2) by peripheral blood leukocytes in children living in urban Brazil and investigate the role of IL-10 in modifying this effect. Our data showed that the proportion of children producing Th1 and Th2 cytokines was lower among those with poor living conditions and that this finding was stronger in children producing IL-10. These results provide a possible biologic explanation for the temporal trends of increasing risk of inflammatory diseases observed in populations living in affluent countries.