Response of BALB/c mice to a monovalent influenza A （H1N1） 2009 split vaccine

The novel influenza A (H1N1) 2009 virus has emerged to cause the first pandemic of the twenty-first century. Disease outbreaks caused by the influenza A (H1N1) virus have prompted concerns about the potential for a pandemic and have driven the development of vaccines against this subtype of influenza A. In this study, we developed a monovalent influenza A (H1N1) split vaccine and evaluated its effects in BALB/c mice. Mice were immunized subcutaneously with 2 doses of the vaccine containing hemagglutinin (HA) alone or HA plus an aluminum hydroxide (Al(OH)₃) adjuvant. Immunization with varying doses of HA (3.75, 7.5, 15, 30, 45 or 60 µg) was performed to induce the production of neutralizing antibodies. The vaccine elicited strong hemagglutination inhibition (HI) and microneutralization, and addition of the adjuvant augmented the antibody response. A preliminary safety evaluation showed that the vaccine was not toxic at large doses (0.5 ml containing 60 µg HA+600 µg Al(OH)₃ or 60 µg HA). Moreover, the vaccine was found to be safe at a dose of 120 µg HA+1200 µg Al(OH)₃ or 120 µg HA in 1.0 ml in rats. In conclusion, the present study provides support for the clinical evaluation of influenza A (H1N1) vaccination as a public health intervention to mitigate a possible pandemic. Additionally, our findings support the further evaluation of the vaccine used in this study in primates or humans.     

禽流感H5N1亚型病毒感染BALB/c小鼠的免疫应答

目的 研究禽流感H5N1病毒感染BALB/c小鼠后对宿主细胞免疫功能和细胞因子水平变化的影响,探讨禽流感H5N1病毒感染哺乳动物的免疫发病机制.方法 选用鹅源禽流感H5N1病毒感染BALB/c小鼠,采用流式细胞仪检测血液和脾脏T淋巴细胞及其亚群的变化,采用ELISA检测血液中细胞岗子(IFN-γ、TNF-α、IL-4、IL-18、IL-10、IL-2)及禽流感H5N1病毒特异性抗体的变化.结果 禽流感H5N1病毒感染可引起对宿主短暂的、可恢复的细胞免疫功能损伤:血液CD3+、CD4+、CD8+ T淋巴细胞数量于染毒后第2～4天下降(第4天为最低值),脾脏T淋巴细胞数最于染毒后第5～8天下降(第6天为最低值),然后均逐渐恢复到正常水平.染毒后血液细胞因子变化表现为:血清IFN-γ、TNF-α水平下降,IL-4、IL-18、IL-10水平上升,IL-2水平无明显变化.从感染第7天开始检测H5N1禽流感特异性抗体为阳性,抗体水平逐渐升高至实验结束的感染第14天.结论 H5N1禽流感病毒感染可引起宿主T细胞免疫功能低下是其主要的免疫病理改变之一,细胞因子表达失平衡或过多的表达都可能对宿主产生免疫病理损伤.

Abstract：

Objective To study the cell immunity and eytokines responses to avian influenza A H5N1 virus infections in a BALB/c model to better understand the pathogenesis of H5N1 avian influenza disease. Methods Two hundred and twenty BALB/c mice of the infected group were inoculated with 0.1 ml (10-4.875 TCID50) of A/Goose/Guangdong/NH/2003 ( H5N1 ) virus intra-nasally. Fifty control mice received noninfectious allantoic fluid and another fifty control mice received normal sodium. Blood and spleen samples were collected from the live mice every 24 h during the 14 d post-infection. The changes of CD3 + T cells , CD4 + T cells, CD8 + T cells for cell immunity in blood circulation and spleen were detected by flow cytometry. And the cytokines and antibody responses in blood circulation were detected by ELISA. Necropsy was performed on mice that died during the experiment and those euthanized at end of study. Results Avian influenza A( H5N1) virus infections can make damages to the cell immune system transiently. The CD3 + T cells, CD4 + T cells, CDS + T cells declined at 24 days post infection in blood circulation and declined at 5-8 days in spleen, then recovered to the normal level gradually. The eytokines responses to the infections can be detected: the level of IFN-γ,TNF-α declined, IL-4, IL-18, IL-10 increased, and IL-2 changed little. The antibody increased rapidly from day 7 post infection until the end of the study (day 14 post infection). Conclusion Collectively, avian influenza A(H5N1) virus can cause cell immunity deficiency and an imbalance in the level of eytokines, which may contribute to the unusual severity of disease caused by the H5N1 avian influenza virus.     

Differential sensitivity to transforming growth factor (TGF)-{beta} of CBA and of CBA/N B cells demonstrates that the IgG2b inducing factor in synovial fluid from rheumatoid arthritis patients is not identical to TGF-{beta}

Synovial fluid from patients with rheumatoid arthritis (RA-SF)contains in vivo produced cytokines and inflammatory mediators,including a factor that induces IgG2b production of lipopolysaccharide(LPS) preactivated murine B lymphocytes. In order to determinethe mechanism by which RA-SF acts on LPS activated mouse B cells,CBA/N mice were used as an experimental model. The X-linkedimmunodeficiency of these mice is caused by a point mutationin the Bruton's tyrosine kinase (btk) gene. We have earliershown that RA-SF can reconstitute the CBA/N B cell deficiencyin vitro and in vivo, with regard to IgG2b production afterLPS stimulation. Since transforming growth factor (TGF)-ßhas been suggested to be a switch factor for IgG2b, we aimedat investigating the role of TGF-ß in our experimentalsystem. We found that TGF-ß could not mimic the effectof RA-SF on CBA spleen cells. A small increase of IgG2b secretionwas observed with spleen cells from normal CBA mice, whereasIg secretion of all isotypes was suppressed in CBA/N spleencells treated with TGF-ß at any concentration. Neutralizingantibodies against TGF-ß suppressed the response ofCBA B cells, whereas the response by CBA/N B cells was enhancedby the same antibody preparation. Here we also show that theabnormal B cell responsiveness to TGF-ß, typical ofCBA/N, co-segregates with the btk mutation in male (CBA x CBA/N)F₂spleen cells. This was determined by allele specific PCR recognizingthe identified base substitutions of the btk gene, typical ofthe two strains. We propose that RA-SF contains a factor, separatefrom TGF-ß, that is involved in the differentiationof IgG2b expressing cells.     

The use of immunodeficient male (CBA/N x BALB/c) F1 mice to produce monoclonal antibodies directed to proteins of Leptospira interrogans rather than to immunodominant lipopolysaccharides.

A method, using an immunodeficient mouse strain, for the production of monoclonal antibodies directed exclusively against the proteins in an antigen mixture also containing immunodominant LPS, is described. Male (CBA/N x BALB/c) F1 mice were immunized with an outer envelope antigen mixture from Leptospira interrogans strain Wijnberg containing both lipopolysaccharides and proteins. The immune response in these mice was shown to be predominantly directed against protein antigens. Hybridoma cell lines were generated by fusing spleen cells from a (CBA/N x BALB/c) F1 mouse with BALB/c Sp2/0 plasmacytoma cells. Hybridoma cell lines producing monoclonal antibodies reacting with the outer envelope preparation were identified by ELISA. All epitopes recognized by the monoclonal antibodies are sensitive to proteinase K degradation and resistant to oxidation by periodate indicating that they are located on proteins. All epitopes are located on a 35 kDa protein and specific for the pathogenic L. interrogans species.     

Complex pattern of Th1 and Th2 activation with a preferential increase of autoreactive Th1 cells in BALB/c mice with proteoglycan (aggrecan)-induced arthritis

The central role of CD4+ T cells and the balance between T helper (Th) subpopulations in the pathogenesis of autoimmune diseases have been extensively studied. Proteoglycan (aggrecan)-induced arthritis (PGIA) is a murine model for rheumatoid arthritis (RA), which is characterized by a Th1 dominance at the onset of the disease. In addition to CD4+ T cells, antigen-presenting B cells and autoantibodies seem to play an important role in the development and regulation of PGIA. To identify proteoglycan-specific CD4+ T cell subsets and Th1- and Th2-supported antibody isotypes during the progression of PGIA, spleen cells of proteoglycan-immunized BALB/c mice were harvested at different times of immunization, and at different stages of the disease, and their cytokine production and antigen-specific antibody isotype profiles were determined by enzyme-linked immunospot (ELISPOT) assays. Both Th1 and Th2 cytokine-producing cells, with the predominance of IL-4/IL-5-secreting cells, were detected during the prearthritic stage, and a shift toward a Th1 dominance was observed at the time of onset of arthritis. Tissue homogenates of acutely inflamed joints contained significantly higher levels of interferon-gamma than IL-4. The prearthritic period and both the acute and chronic phases of joint inflammation were characterized by IgG1 dominance in the sera and this correlated with the number of IgG1-secreting B cells in the spleen. However, the ratio of autoreactive IgG1/IgG2a-secreting cells decreased in arthritic animals. These results indicate the activation and possible regulatory roles of both Th1 and Th2 subsets in the autoimmune process, with the necessity of a relative increase of autoreactive Th1 cells for the induction of joint inflammation.     

Dissimilar background genes control susceptibility to autoimmune disease in the context of different MHC haplotypes: NOD.H-2(s) congenic mice are relatively resistant to both experimental autoimmune encephalomyelitis and type I diabetes

Nonobese diabetic (NOD) mice develop multi-organ autoimmune diseases, including type 1 diabetes. We hypothesized that backcrossing the MHC region from SJL (H-2(s)) mice, which have an endogenous PLP(139-151)-reactive repertoire, onto the background of autoimmune-prone NOD mice would result in a mouse strain that is highly susceptible to experimental autoimmune encephalomyelitis (EAE). Unexpectedly, although we detected an endogenous PLP(139-151) repertoire in the NOD.S mice, they did not develop spontaneous EAE and were relatively resistant to PLP(139-151)-induced EAE when compared to SJL mice. This resistance was associated with lower production of proinflammatory cytokines and a decreased expansion of PLP(139-151)-specific CD4(+) T cells after immunization and restimulation with PLP peptide in vitro. V(beta) chain usage among PLP(139-151)-reactive T cells differed between SJL and NOD.S mice. Furthermore, NOD.S mice were resistant to the development of insulitis and cyclophosphamide-induced diabetes, but not sialadenitis. Altogether, even though NOD mice develop spontaneous autoimmune diseases, they become relatively resistant to induction of EAE even when they express the EAE-permissive class II molecule I-A(s). Our data show that certain combinations of otherwise susceptibility-conferring MHC and non-MHC genes can mediate autoimmune-disease resistance when they are paired together. These findings do not support the "shared autoimmune gene" hypothesis.     

两株登革2型病毒NS1基因真核重组质粒免疫BALB/c小鼠产生特异性抗体水平的比较

目的 利用登革2型病毒(dengue type 2 virus,DENV2)M株和NGC株NS1基因部分扇列PcDNA3.1重组质粒初次和加强免疫BALB/c小鼠,观察免疫小鼠体液免疫应答的差异.方法 分别构建两株DENV2 NS1基因部分序列(1-413 bp)的PcDNA3.1真核重组质粒和pET28a(+)质粒,进行原核蛋白的表达、鉴定、纯化和定量;并用pcDNA3.1重组质粒免疫BALB/c小鼠,初次免疫及第7天、14天分别加强免疫1次,共免疫3次.收集初次免疫后第7、14、28和56天外周血标本,间接ELISA法测定小鼠血清特异性IgM/IgG类抗体水平,细胞病变抑制法检测特异保护性抗体水平.结果 构建了pET28a(+)-NS1m/pET28a(+)-NS1n原核表达重组质粒,SDS-PAGE分析表明,NS1基因部分序列获得表达,其相对分子质量均约22.3×103;Western blot表明该目的 蛋白可与抗His标签单克隆抗体结合;经Ni柱亲和层析法得到纯度达92%的表达蛋白,对C6/36细胞有毒性,并可用于ELASA检测.不同DENV2毒株NS1基因部分序列的pcDNA3.1重组质粒初次和加强免疫BALB/c小鼠诱导特异性IgM、IgG类和中和抗体的产生存在差异,M株重组质粒加强免疫小鼠后特异性抗体效价水平较高并持续较长时间.结论 DENV2两毒株NS1基因部分序列重组质粒免疫小鼠后诱生的特异性抗体类别、水平存在差异.

Abstract：

Objective To compare the humoral immune response of BALB/c mice immunized by recombinant plasmids PeDNA3.1-M-NS1 and pcDNA3.1-N-NS1.Methods Dengue type 2 virus(DENV2)NS1 gene were constructed two partial sequences(1-413 bp)of the pcDNA3.1 eukaryotic plasmids and pET28a(+)plasmid for prokaryotic expression,identification,purification and quantification.The BALB/c mice were immunized by pcDNA3.1-M-NS1,pcDNA3.1-N-NS1 recombinant plasmids with adjuvant.Each animal received a primary inoculation and two boosts at 1-week intervals.Then the blood samples of BALB/c mice were collected from different experiment groups at day 7,14,28 and 56,respectively after first immunization.The specific IgM/IgG antibodies for NS1 protein in serum were confirmed by indirect ELISA.And then the activities of the specific protective antibody were determined by cytopathic effect inhibition(CPEI).Results Construction of the pET28a(+)-NS1 m/pET28a(+)-NS1n prokaryotic expression plasmid,SDS-PAGE analysis showed that,NS1 gene partial sequence was expressed,both the relative molecular weight of about 22.3×103:Western blot showed that the protein can bind anti-His tag monoclonal antibody;byNi affinity chromatographywith apurity of 92% protein,on the C6/36 cell toxicity,and can be used ELASA detection.The results showed that the levels of specific IgM/IgG antibody and neutralizing antibody activities were increased in pcDNA3.1-M-NS1 booster immunization group than other groups.The result had been observed longer duration of antibody level in peDNA3.1-M-NS1 booster immunization group.Conclusion Humoral immune response were significantly different between pcDNA3.1-M-NS1 and pcDNA3.1-N-NS1 recombinant plasmid immunized mice groups.     

Regulatory proteins for the activated third and fourth components of complement (C3b and C4b) in mice. I. Isolation and characterization of factor H: the serum cofactor for the C3b/C4b inactivator (factor I)

Factor H, purified from mouse EDTA-plasma using a 4-step procedure, consists of a single polypeptide chain of Mr 150,000 on SDS-PAGE. Mouse H (Hmo) was required for the cleavage of fluid-phase mouse C3b by mouse I (Imo). The final product of degradation of fluid-phase mouse C3b was iC3b, consisting of fragments of the alpha'-chain (alpha'-70, alpha'-43) linked by disulfide bonds to an intact beta-chain. Imo alone was capable of cleavage of membrane-bound mouse C3b and of generating iC3b. The addition of Hmo nevertheless had an enhancing effect on Imo activity, but cleavage did not proceed beyond iC3b. These observations suggest that one important function of Hmo is to permit the inactivation of fluid-phase C3b, and to inhibit irreversibly its activity. The concentration of H in the plasma of male and female BALB/c mice was not significantly different. Among different inbred strains of mice, large differences were observed in the plasma levels of H, and plasma H levels were positively correlated with the plasma levels of C3. This observation, taken together with the well known role of H in the control of the activation of the alternative pathway, suggests that the turnover of C3 is controlled to some extent by H.