再障和溶贫患者外周血CD55及CD59的表达及意义

目的 检测再生障碍性贫血(AA)及溶血性贫血患者外周血细胞中CD55、CD59的表达情况,并探讨其临床意义.方法 用荧光素标记CD55、CD59单克隆抗体,采用流式细胞术测定30名正常人、12例AA及20例溶贫患者外周血红细胞和中性粒细胞(PMN)中CD55、CD59表达情况.结果 正常人红细胞及中性拉细胞CD55、CD59标记率均＞95%,12例AA患者中7例标记率正常,另外5例患者有不同程度的减低,溶血性贫血患者的标记率均正常.结论 流式细胞术检测再障患者CD55、CD59表面抗原有重要意义,可以早期发现再障-阵发性睡眠性血红蛋白尿综合征.     

The emerging role of innate immunity in protection against HIV-1 infection

Preventive immunization against HIV-1 infection requires a rapid immune response that does not rely exclusively on B or T cell memory. Innate immunity may fulfill this function as it may be activated directly at the time of HIV-1 transmission, inhibit early HIV-1 replication, stimulate adaptive immunity and enable specific antibodies followed by CD8(+) T cells to deal with the virus effectively. The three components of innate immunity - cellular, extracellular and intracellular - are presented, with an example given for each of these components; gammadelta T cells, CC chemokines and APOBEC3G. This brief account is presented to highlight the immuno-virological concept of coordinating activated innate immunity with adaptive antibody and T cell responses in preventive vaccination against HIV-1 infection.     

Radiation protection by diethyldithiocarbamate: protection of membrane and DNA in vitro and in vivo against gamma-radiation

Diethyldithiocarbamate (DDTC) is studied for its antioxidant and radioprotective abilities. DDTC at a concentration of 0.5 mM reduced DPPH radical. DDTC reduced the damage to deoxyribose resulting from hydroxyl radicals generated by Fenton reaction, indicating that the radioprotective abilities of this compound could be due to the free radical scavenging. DDTC protected rat liver microsomal membranes in vitro from peroxidative damage in lipids (measured as TBARS) resulting from 50 Gy gamma-radiation. It also protected plasmid pBR322 DNA from radiation-induced strand breaks. An oral administration of DDTC to mice before whole body gamma-radiation exposure (4 Gy) resulted in a reduction of radiation-induced lipid peroxides in the liver homogenates. An administration of DDTC to mice before gamma-radiation reduced the radiation-induced DNA damage as studied by single cell gel-electrophoresis (comet assay). The comet parameters such as tail length, tail moment, and percent of DNA in tail were found to increase in the blood leukocytes of mice exposed to 4 Gy gamma-radiation. When DDTC was administered to mice before the radiation exposure, the increase in the comet parameters as a result of radiation was prevented, indicating a protection of cellular DNA. The present study has implication for the potential use of DDTC as a radioprotector.     

Radiation protection by disulfiram: protection of membrane and DNA in vitro and in vivo against gamma-radiation

Disufiram (a drug used for the treatment of alcoholism) protected microsomal membranes and plasmid DNA against damages induced by gamma-radiation. The peroxidation of membrane lipids increased linearly with the radiation dose up to 600 Gy, and the presence of disulfiram inhibited membrane lipid peroxidation as assayed by the presence of thiobarbituric acid reacting substances. The reduction of the quantity of the supercoiled (ccc) form of plasmid pBR322 DNA is directly related to the radiation-induced damage, particularly to DNA strand breaks. There was a complete protection of plasmid DNA when exposed to gamma-radiation in the presence of disufiram (0.1 mM) at 300 Gy. This drug also protected deoxyribose against damages caused by hydroxyl radicals produced by the Fenton reaction. The administration of DSF to mice prior to whole-body radiation exposure (4 Gy) resulted in a reduction of peroxidation of membrane lipids in mice liver as well as a decrease in radiation-induced damage to cellular DNA, as assayed by single-cell gel electrophoresis (comet assay). The results thus suggest the possible use of DSF as a radioprotector.     

Single-dose, virus-vectored vaccine protection against Yersinia pestis challenge: CD4+ cells are required at the time of challenge for optimal protection

We have developed an experimental recombinant vesicular stomatitis virus (VSV) vectored plague vaccine expressing a secreted form of Yersinia pestis low calcium response protein V (LcrV) from the first position of the VSV genome. This vector, given intramuscularly in a single dose, induced high-level antibody titers to LcrV and gave 90-100% protection against pneumonic plague challenge in mice. This single-dose protection was significantly better than that generated by VSV expressing the non-secreted LcrV protein. Increased protection correlated with increased anti-LcrV antibody and a bias toward IgG2a and away from IgG1 isotypes. We also found that the depletion of CD4+ cells, but not CD8+ cells, at the time of challenge resulted in reduced vaccine protection, indicating a role for cellular immunity in protection.     

The role of complement in experimental silicosis

The role of the complement system in the pathogenesis of crystal-induced pulmonary inflammation and fibrosis was evaluated using a mouse model of silicosis and congenitally complement-deficient mice. Mice lacking the fifth component of complement (B10.D2/o) were compared to C5-sufficient animals (B10.D2/n) for pulmonary changes following intratracheal instillation of silica crystals. Complement-deficient mice demonstrated a significant reduction compared to complement-sufficient mice in both cell number and protein content of lung lavage fluid throughout the 12 weeks following silica exposure. Lung hydroxyproline content (indicative of collagen deposition) was equivalent for both strains and significantly higher than controls at all time points following silica instillation. Moreover, studies in vitro have shown that silica crystals are capable of activating complement via the alternative pathway. These studies indicate that the complement system may be responsible for some of the pulmonary inflammation, but not fibrosis elicited by silica exposure.     

T cells play an essential role in anti-F1 mediated rapid protection against bubonic plague

Plague, which is initiated by Yersinia pestis infection, is a fatal disease that progresses rapidly and leads to high mortality rates if not treated. Antibiotics are an effective plague therapy, but antibiotic-resistant Y. pestis strains have been reported and therefore alternative countermeasures are needed. In the present study, we assessed the potential of an F1 plus LcrV-based vaccine to provide protection shortly pre- or post-exposure to a lethal Y. pestis infection.Mice vaccinated up to one day before or even several hours after subcutaneous challenge were effectively protected. Mice immunized one or three days pre-challenge were protected even though their anti-F1 and anti-LcrV titers were below detection levels at the day of challenge. Moreover, using B-cell deficient μMT mice, we found that rapidly induced protective immunity requires the integrity of the humoral immune system. Analysis of the individual contributions of vaccine components to protection revealed that rF1 is responsible for the observed rapid antibody-mediated immunity. Applying anti-F1 passive therapy in the mouse model of bubonic plague demonstrated that anti-F1 F(ab′)₂ can delay mortality, but it cannot provide long-lasting protection, as do intact anti-F1 molecules. Fc-dependent immune components, such as the complement system and (to a lesser extent) neutrophils, were found to contribute to mouse survival. Interestingly, T cells but not B cells were found to be essential for the recovery of infected animals following passive anti-F1 mediated therapy. These data extend our understanding of the immune mechanisms required for the development of a rapid and effective post-exposure therapy against plague.     

青石棉诱导AL细胞CD59基因突变和DNA氧化损伤的研究

目的　研究谷胱甘肽合成酶抑制剂buthioninesulfoximine(BSO)和自由基清除剂二甲亚砜 (DMSO)对青石棉诱导人鼠杂交瘤 (AL)细胞CD59基因突变率的影响以及青石棉引发细胞内 8 羟基脱氧鸟苷 (8 OHdG)产生的规律。方法　细胞毒性、遗传毒性检测分别采用克隆法 ;8 OHdG检测采用ABC酶免疫染色法 ;非蛋白巯基化合物 (NPSH)检测采用改进后的Tietze法。结果　 2 5μmol/LBSO预处理AL 细胞 2 4h后的细胞内NPSH含量降为 2nmol/ 10 7细胞 ,仅为对照组的 5%。青石棉单独处理组AL 细胞CD59基因突变率为 2 0 8± 18。BSO预处理 2 4h后与青石棉继续共同孵育组细胞突变率可达到 3 97± 55,是青石棉单独处理组的 2倍左右 ,差异有显著性 (P <0 .0 5) ;而DMSO存在时 ,青石棉诱导的CD59基因突变率仅为 57± 8,比青石棉单独处理组降低 72 .6%。细胞内 8 OHdG的产生随着青石棉处理剂量的增加而线性增加 (y =150 2 0x ,r =0 .962 1)。当青石棉处理剂量为 6μg/cm2 时 ,细胞内 8 OHdG含量由对照组的 13 7± 9提高到 2 89± 6,是对照组的 2倍以上。DMSO存在时 ,可使 6μg/cm2 石棉诱导的细胞内 8 OHdG含量由 2 89± 6降低到 170± 3。结论　自由基是青石棉诱导基因突变和DNA损伤过程中重要的调节物 ,具有剂量 -效应关系     

A potential role for CD25+ regulatory T-cells in the protection against casein allergy by dietary non-digestible carbohydrates

Dietary non-digestible carbohydrates reduce the development of cows' milk allergy in mice. In the present study, the contribution of CD25+ regulatory T-cells (Treg) was investigated using in vivo Treg depletion and adoptive transfer studies. Mice were orally sensitised with casein and fed a diet containing 2?% short-chain galacto-, long-chain fructo- and acidic oligosaccharides (GFA) or a control diet. Donor splenocytes of mice sensitised with casein and fed the GFA or control diet were adoptively transferred to naive recipient mice, which were casein- or sham-sensitised and fed the control diet. In addition, in vivo or ex vivo CD25+ Treg depletion was performed using anti-CD25 (PC61). The acute allergic skin response upon intradermal casein challenge and casein-specific Ig were determined. Furthermore, T-helper (TH) 1 and TH2 cell numbers were analysed in the mesenteric lymph nodes. The oligosaccharide diet strongly reduced the development of the acute allergic skin response, which was abrogated by the in vivo anti-CD25 treatment. The diet enhanced the percentage of TH1 cells and tended to reduce the percentage of TH2 cells in casein-sensitised mice. Recipient mice were protected against the development of an acute allergic skin response when transferred with splenocytes from casein-sensitised GFA-fed donor mice before sensitisation. Ex vivo depletion of CD25+ Treg abrogated this transfer of tolerance. Splenocytes from sham-sensitised GFA-fed donor mice did not suppress the allergic response in recipient mice. In conclusion, CD25+ Treg contribute to the suppression of the allergic effector response in casein-sensitised mice induced by dietary intervention with non-digestible carbohydrates.     

Effective CD8 T cell priming and tumor protection by enterotoxin B subunit-conjugated peptides targeted to dendritic cells

In our previous studies we have shown that bacterial enterotoxin B subunits are effective vehicles to deliver antigen into the MHC class I processing route. Here we have used the non-toxic Escherichia coli heat labile enterotoxin B subunit (EtxB) conjugated to OVA peptide (EtxB–peptide) to address the impact on induction of specific CD8⁺ T cells in vivo. Although incubation of DCs with these EtxB–peptide conjugates as such did not induce DC maturation in vitro MHC class I antigen presentation was much more efficient as compared to peptide alone. Antigen presentation was further enhanced upon DC maturation with the TLR-4 ligand LPS. Injection of matured DCs incubated with EtxB–peptide conjugates lead to strong induction of OVA-specific CD8⁺ T lymphocytes and fully prevented the outgrowth of lethal B16 melanoma in wild type mice. Our data demonstrate that bacterial non-toxic B subunit–peptide conjugates are potent vaccine vehicles for induction of protective CD8⁺ T cell responses.     

Antibody-induced lysis of isolated rat epididymal adipocytes and complement activation in vivo

OBJECTIVE: To identify human monoclonal antibodies selectively binding to human adipocytes and to evaluate their ability to induce lysis of isolated rat adipocytes in vitro and to reduce rat complement levels in vivo. RESEARCH METHODS AND PROCEDURES: Using phage display technology, human monoclonal antibodies binding to human adipocyte plasma membranes were identified. Three antibodies (Fat 13, Fat 37, and Fat 41) were selected based on their additional cross-reaction with rat adipocytes and reformatted as a rat chimeric IgG2bs. The ability of these antibodies, both singly and in combination, to induce lysis of rat epididymal adipocytes in vitro and the reduction of serum complement levels in vivo in the rat was evaluated. RESULTS: All antibodies caused similar time- and dose-dependent lysis of isolated rat adipocytes. Calculated mean EC(50) values (maximum percentage of lysis in parentheses) were 0.680 microg/mL (63.2%), 0.546 microg/mL (72.4%), and 0.391 microg/mL (73.7%) for Fat 13, Fat 37, and Fat 41, respectively. Combinations were no more effective than individual antibodies in inducing lysis. Anti-adipocyte antibodies (both singly and in combination) were also similarly effective in vivo. In rats, doses of monoclonal antibody up to 10 mg/kg intraperitoneal generally caused almost complete depletion of serum complement up to 24 hours after dosing recovering to baseline values by day 5. DISCUSSION: Individual and combinations of monoclonal anti-adipocyte antibodies produced a complement-dependent and concentration-dependent activity to lyse adipocytes in vitro and in vivo as measured by a dramatic depletion in serum complement.     

Dendritic cells transfected with Her2 antigen-encoding RNA replicons cross-prime CD8 T cells and protect mice against tumor challenge

Antigen-specific T cells can be induced by direct priming and cross-priming. To investigate cross-priming as a vaccination approach dendritic cells were transfected with cytopathogenic viral RNA-replicons that expressed domains of the tumor-associated Her2-antigen and injected into MHC-discordant mice that did not allow direct priming. Upon tumor challenge 75% of the vaccinated, but none of the mock-vaccinated mice remained tumor-free. The anti-tumor effect required T cells and correlated with the vigor of the cross-primed CD8 T cell response. Her2-specific antibodies were not detected. This study highlights the potential of T cell cross-priming in cancer immunotherapy.     

The role of the complement system in the defence against infections and new ways of assessing the activation routes

The complement system is of major importance in the defence against infections. Deficiencies in one of the three pathways of activation of the complement system can cause serious infections; the classical pathway, the alternative pathway and the lectin pathway. A new ELISA assay has been developed to enable the assessment of the functional activity of the whole lectin pathway and to determine the classical and the alternative pathway functional activity in a simple uniform design.     

CD55对子宫内膜的影响及可能机制

妊娠的建立依赖于子宫内膜正常的功能状态,CD55在分泌期子宫内膜表达逐渐上调并在分泌中期达到峰值,而CD55的异常表达与反复流产和着床失败、子宫内膜异位症、内膜癌等多种子宫内膜相关疾病有关。除了作为补体调节蛋白抑制补体介导的细胞杀伤作用以外,CD55在子宫内膜中还参与调节细胞周期,促进细胞增殖抑制凋亡,促进细胞侵袭迁移...     

Functional role of respiratory tract haemagglutinin-specific IgA antibodies in protection against influenza

Intranasal inoculation of haemagglutinin (HA) purified from influenza virus A/PR/8/34 (PR8, H1N1) together with cholera toxin B subunit, into Balb/c mice resulted in complete protection against PR8 infection in parallel with the induction of high levels of HA-specific IgA and IgG antibodies on the respiratory tract. The respiratory tract IgA and IgG were purified from nasal and lung washings of the immunized mice using affinity columns, and their HA-specific activities were measured by enzyme-linked immunosolvent, plaque neutralization and haemagglutination inhibition assays. The purified IgA and IgG had the following properties: (1) They were able to neutralize virus in vitro. (2) The purified IgA included major antibodies directed against PR8 virus and minor antibodies cross-reactive with A/Yamagata/120/86 (H1N1) or A/Fukuoka/C29/85 (H3N2) virus, while the purified IgG included major antibodies to the homotypic virus, minor antibodies to the H1N1 virus and only a trace amount of antibodies to the H3N2 virus. (3) When separated on a Sephacryl column, most of the IgA anti-HA activities occurred in the polymeric fractions of purified IgA, whereas the IgG anti-HA activities occurred in the monomeric fractions. (4) When passively administered to normal mouse respiratory tract before infection, the purified IgA protected against PR8 infection. These results suggest that HA-specific, polymeric IgA antibodies on the respiratory tract by themselves provide not only protection against the homotypic virus but also higher levels of heterotypic immunity than IgG.     

CD80 and CD86, but not CD154, augment DNA vaccine-induced protection in experimental bovine tuberculosis

DNA vaccination is known to elicit robust cellular and humoral responses to encoded antigen. The co-administration of costimulatory molecules CD80 (B7-1), CD86 (B7-2) and CD154 (CD40L) has been shown to enhance immune responses in several murine models. The role of specific costimulatory molecules in non-rodent species remains incompletely characterized. In these studies, we demonstrate that the co-administration of CD80 and CD86, but not CD154, to an existing candidate subunit DNA vaccine (ESAT-6) against bovine tuberculosis, enhances protection after aerosol challenge with virulent Mycobacterium bovis. Additionally, we have shown that vaccination with M. bovis BCG is protective against tuberculosis following aerosol challenge in cattle. Two independent trials were conducted in cattle to determine the adjuvant effect of encoded antigen + CD80/CD86 and directly compare the adjuvant activities of CD80/CD86 to those of CD154. Co-administration of either CD80/CD86 or CD154 enhanced ESAT-6-specific IFN-gamma responses as compared to animals vaccinated with ESAT-6 DNA alone. However, following aerosol challenge, only animals vaccinated with CD80/CD86 possessed decreased pathology of the lungs and associated lymph nodes, as measured by gross examination, radiographic lesion morphometry and bacterial recovery. Collectively, these results demonstrate that the co-administration of costimulatory molecules with a protective antigen target enhances bovine immune responses to DNA vaccination, and that CD80/CD86 is superior to CD154 in augmenting DNA vaccine-induced protection in experimental bovine tuberculosis.     

Further analysis of protection induced by the MIC3 DNA vaccine against T. gondii: CD4 and CD8 T cells are the major effectors of the MIC3 DNA vaccine-induced protection,both Lectin-like and EGF-like domains of MIC3 conferred protection

The present study was conducted mainly to evaluate the contribution of the cellular and the humoral responses in protection conferred by the MIC3 DNA vaccine (pMIC3i) that was proved as a potent vaccine against toxoplasmosis. We performed the adoptive transfer of CD4⁺ and CD8⁺ T lymphocytes from pMIC3i immunized mice to naive ones and the role of humoral immunity was evaluated by in vitro invasion assays. We also constructed plasmids encoding the EGF-like domains and the Lectin-like domain of MIC3, to define which domains of MIC3 are involved in the protection. Furthermore, the adjuvant effect of the GM-CSF-expressing vector (granulocyte-macrophage colony-stimulating factor) required the precise temporal and spatial codelivery of GM-CSF with antigen, thus, we constructed a bicistronic plasmid expressing MIC3 and GM-CSF. In conclusion, the protection induced by pMIC3i was mainly mediated by CD4⁺ and CD8⁺ T lymphocytes and both EGF and Lectin domains of MIC3 conferred protection. Furthermore, the codelivery of GM-CSF by a bicistronic plasmid appeared to be a most effective way for enhancing the adjuvant properties of GM-CSF.     

The activity against Trypanosoma cruzi and cutaneous leishmaniasis,and toxicity,of moxipraquine (349C59)

A novel 8-aminoquinoline compound, 8{6-4′ (3 — hydroxybutyl)piperazin — 1′ — ylhexylamino} — 6 —methoxyquinoline di(hydrogen maleate), moxipraquine, 349C59, was shown to be active against experimental infections with Trypanosoma cruzi. It was effective in suppressing parasitaemia but did not eradicate the infection from mice or guinea-pigs. Other clinically tested drugs, including nifurtimox, were likewise incapable of eradicating the parasite from infected mice. Moxipraquine was less potent against mouse infections with strain Peru than it was against other strains of T. cruzi. In limited tests, moxipraquine was effective on experimental infections of Leishmania major, L. mexicana mexicana and L. brasiliensis panamensis but not L.b. brasiliensis. Significant foetal toxicity, observed experimentally in rats and rabbits, resulted in the termination of clinical trials.