A combination of Flt3 ligand cDNA and CpG oligodeoxynucleotide as nasal adjuvant elicits protective secretory-IgA immunity to Streptococcus pneumoniae in aged mice

Our previous study showed that a combination of a plasmid-expressing Flt3 ligand (pFL) and CpG oligodeoxynucleotides (CpG ODN) as a combined nasal adjuvant elicited mucosal immune responses in aged (2-y-old) mice. In this study, we investigated whether a combination of pFL and CpG ODN as a nasal adjuvant for a pneumococcal surface protein A (PspA) would enhance PspA-specific secretory-IgA Ab responses, which could provide protective mucosal immunity against Streptococcus pneumoniae infection in aged mice. Nasal immunization with PspA plus a combination of pFL and CpG ODN elicited elevated levels of PspA-specific secretory-IgA Ab responses in external secretions and plasma in both young adult and aged mice. Significant levels of PspA-specific CD4(+) T cell proliferative and PspA-induced Th1- and Th2- type cytokine responses were noted in nasopharyngeal-associated lymphoreticular tissue, cervical lymph nodes, and spleen of aged mice, which were equivalent to those in young adult mice. Additionally, increased numbers of mature-type CD8, CD11b-expressing dendritic cells were detected in mucosal inductive and effector lymphoid tissues of aged mice. Importantly, aged mice given PspA plus a combination of pFL and CpG ODN showed protective immunity against nasal S. pneumoniae colonization. These results demonstrate that nasal delivery of a combined DNA adjuvant offers an attractive possibility for protection against S. pneumoniae in the elderly.     

In vivo polysaccharide-specific IgG isotype responses to intact Streptococcus pneumoniae are T cell dependent and require CD40- and B7-ligand interactions.

In vivo Ig responses to soluble, haptenated polysaccharide (PS) Ags are T cell independent and do not require CD40 ligand (CD40L). However, little is known regarding the regulation of in vivo PS-specific Ig responses to intact bacteria. We immunized mice with a nonencapsulated, type 2 Streptococcus pneumoniae (R36A) and compared the parameters that regulated in vivo Ig isotype responses to the bacterial cell wall C-PS determinant, phosphorylcholine (PC), relative to Ig responses to the cell wall protein, pneumococcal surface protein A. Consistent with previous reports using soluble PS and protein Ags, the anti-PC and anti-pneumococcal surface protein A responses differed in that the anti-PC response was induced more rapidly, had a distinctive Ig isotype profile, and failed to demonstrate boosting upon secondary challenge with R36A. However, in contrast to previous studies, the IgG anti-PC response was TCR-alphabeta+ T cell dependent, required CD40L, and was blocked by administration of CTLA4 Ig. The nature of the T cell help for the anti-PC response had distinct features in that it was only partially blocked by CTLA4 Ig and was dependent upon both CD4+ and CD8+ T cells. Surprisingly, whereas the IgM anti-PC response was largely T cell independent, a strong requirement for CD40L was still observed, suggesting the possibility of an in vivo T cell-independent source for CD40L-dependent help. These data suggest that the regulatory parameters that govern in vivo Ig responses to purified, soluble PS Ags may not adequately account for PS-specific Ig responses to intact bacteria.     

Patients with Wiskott-Aldrich syndrome have normal IgG2 levels

The Wiskott-Aldrich Syndrome (WAS) in humans has a number of similarities to the immunodeficiencies found in CBA/N mice, including X-chromosome-linked inheritance, inability to produce antibodies to various carbohydrate antigens, susceptibility to various bacterial infections, and an imbalance in B lymphocyte subpopulations. Moreover, in both man and mice, IgG antibodies to polysaccharides are predominantly, but not exclusively, restricted to a single IgG subclass--IgG2 in man, and IgG3 in the mouse. Because CBA/N mice have a deficiency of IgG3 antibodies and because human IgG2 subclass deficiencies have been generally associated with inability to produce antibodies to carbohydrate antigens, it would seem likely that patients with WAS would have greatly reduced levels of IgG2. Quite to the contrary, the data presented here demonstrate that WAS patients have normal levels of the different IgG subclasses, including IgG2. Thus, inability to produce antibodies to carbohydrates is not always associated with IgG2 subclass deficiency.     

长白山北坡静水水体中水甲虫分布与环境关系的典范对应分析

应用典范对应分析（CCA）对长白山北坡静水水体12个样点中28种水甲虫与环境关系的研究表明,长白山5种环境因子中水底腐殖化程度和海拔对水甲虫的分布起主要作用,与排序轴的相关系灵敏分别高达0.8371和0.7206,而水温和植被密度也有较大的影响,在环境因子的影响下不同生境中水甲虫分布的种群不同,深刻斜凹龙虱,端钩切眼龙虱,布朗沟牙甲,沼梭科水甲虫等主要分布在深水区,与水温没有关系。而异毛龙虱和舟型牙甲等与海拔和水泡子的腐殖化程度呈正相关。     

A new system for understanding the biodiversity in different nature reserves:capacity,connectivity and quality of biodiversity

In this paper,we propose a new system for understanding the biodiversity in different conservation areas.It includes three aspects:the capacity,the connectivity and the quality.The capacity refers to the numbers of biodiversity,including absolute and relative richness of the vegetation types Nv and Dv = (Nv-1)/lnA,species numbers S and richness of species dGI = (S- 1)/lnA,and germ plasm resources within a nature reserve,and also the potential biological living space offered by the natural resource.It comprises the total biological resources in a nature reserve.The connectivity refers to the flux of biodiversity,including similarity and connected status of the vegetation types SILi = 2z/(x + y) and species numbers SIc = 2z/(x + y) among different nature reserves.The quality refers to the stability of biodiversity,including relative species richness index RSLi = d/dmax,relative vegetation richness index RVLi =Dv/Dmaxv,fastness to invasion species fLi = 1-Si/St,weighted values,representativeness and vulnerability of special vegetations,special species,CITES species and rare species as the protected targets.     

Production and characterization of the functional fragment of pneumococcal surface protein A

Pneumococcal surface protein A (PspA) is present on the cell wall of Streptococcus pneumoniae pathogen and has an antigenetically variable N-terminal domain. This aminoterminal domain is essential for full pneumococcal virulence, and monoclonal antibodies raised against it protect mice against pneumococcal infections. We have cloned and expressed a 34-kDa N-terminal fragment of PspA in Escherichia coli in a soluble form using the T7 RNA polymerase pET-20b vector system. Nickel chelate affinity purification followed by size exclusion and anion exchange chromatography yielded large amounts of pure and homogeneous protein. Analytical ultracentrifugation sedimentation velocity band and boundary studies showed that the molecule was present in aqueous solutions in a monomeric form with an axial shape ratio of approximately 1:12, typical of fibrous proteins. Sequence analyses indicated an alpha-helical coiled-coil structure for this monomeric molecule with only few loop-type breaks in helicity. The mostly alpha-helical structure of this PspA construct was consistent with circular dichroism spectroscopy data. Based on the ultracentrifugation studies, the circular dichroism spectra, and the PspA's sequence analyses, two structural models for the amino-terminal part of the PspA molecule are proposed. The evident highly charged and polar character of the surface of the modeled structures suggests functional properties of PspA that are related to the prevention of S. pneumoniae interactions with the host complement system.     

The Effects of CFTR and Mucoid Phenotype on Susceptibility and Innate Immune Responses in a Mouse Model of Pneumococcal Lung Disease

Recent studies have reported the isolation of highly mucoid serotype 3 Streptococcus pneumoniae (Sp) from the respiratory tracts of children with cystic fibrosis (CF). Whether these highly mucoid Sp contribute to, or are associated with, respiratory failure among patients with CF remains unknown. Other mucoid bacteria, predominately Pseudomonas aeruginosa, are associated with CF respiratory decline. We used a mouse model of CF to study pneumococcal pneumonia with highly mucoid serotype 3 and non-mucoid serotype 19A Sp isolates. We investigated susceptibility to infection, survival, and bacterial counts from bronchoaviolar lavage samples and lung homogenates, as well as associated inflammatory cytokines at the site of infection, and lung pathology. Congenic CFTR^–/– mice and wild-type (WT)-mice were infected intranasally with CHB756, CHB1126, and WU2 (highly mucoid capsular serotype 3, intermediately mucoid serotype 3, and less mucoid serotype 3, respectively), or CHB1058 (non-mucoid serotype 19A). BAL, lung homogenates, and blood were collected from mice 5 days post-infection. Higher CFU recovery and shorter survival were observed following infection of CFTR^–/– mice with CHB756 compared to infection with CHB1126, WU2, or CHB1058 (P≤0.001). Additionally, CFTR^–/– mice infected with CHB756 and CHB1126 were more susceptible to infection than WT-mice (P≤0.05). Between CFTR^–/– mice and WT-mice, no significant differences in TNF-α, CXCL1/KC concentrations, or lung histopathology were observed. Our results indicate that highly mucoid type 3 Sp causes more severe lung disease than non-mucoid Sp, and does so more readily in the lungs of CFTR^–/– than WT-mice.     

Blood clearance of Streptococcus pneumoniae by C-reactive protein

C-reactive protein (CRP) has long been known to be an acute phase protein associated with infection and various forms of tissue damage. Recent studies have shown that human CRP can be used to passively protect mice from lethal infection with Streptococci pneumoniae. In this study we have undertaken a detailed examination of the ability of human CRP and rabbit CRP (CxRP) to mediate the blood clearance of pneumococci in mice. We have shown that the optimal activity of these acute-phase proteins requires a functioning complement system, and it can take place even in the xid mouse, which has virtually no naturally occurring anti-pneumococcal antibody in its serum. These studies provide additional evidence that CRP may play a protective role in pneumococcal infections, and it may help postpone the development of fatal levels of pneumococci in the blood, long enough for an effective anti-pneumococcal antibody response to be generated.