抵抗女性生殖道沙眼衣原体感染的免疫新策略

沙眼衣原体是引起沙眼和泌尿生殖道感染的主要病原体。据世界卫生组织2015年统计,全球每年约有1.3亿沙眼衣原体感染新发病例。研究表明CD4^+Th1型细胞免疫应答在抵抗沙眼衣原体感染中发挥着重要作用。因此,研究者依照抗沙眼衣原体感染的免疫应答特点,构建出许多候选疫苗,但都没有成功地应用于临床。近年研究发现,生殖道黏膜组织不仅存在体液免疫和细胞免疫,还驻留着一些引人注目的免疫细胞,提示增强黏膜免疫可作为预防沙眼衣原体感染的潜在途径,是抵抗生殖道沙眼衣原体感染的免疫新策略。本文全面概述了黏膜免疫与女性生殖道沙眼衣原体感染的研究进展,并为今后研制沙眼衣原体疫苗提供一些建议。     

Chlamydia trachomatis infection alters the development of memory CD8+ T cells

The obligate intracellular bacterium Chlamydia trachomatis is the most common cause of bacterial sexually transmitted disease in the United States and the leading cause of preventable blindness worldwide. Prior exposure to C. trachomatis has been shown to provide incomplete protection against subsequent infection. One possible explanation for the limited immunity afforded by prior C. trachomatis infection is poor activation of Chlamydia-specific memory CD8+ T cells. In this study, we examined the development of CD8+ memory T cell responses specific for the Chlamydia Ag CrpA. The percentage of CrpA63-71-specific T cells expressing an effector memory T cell phenotype (IL-7R+ CD62low) was dramatically diminished in mice immunized with C. trachomatis, compared with mice immunized with vaccinia virus expressing the CrpA protein. These alterations in memory T cell development were correlated with a significant reduction in the capacity of convalescent mice to mount an enhanced recall response to Chlamydia Ags, compared with the primary response. CrpA-specific memory T cells primed during VacCrpA infection also failed to respond to a challenge with Chlamydia. We therefore investigated whether C. trachomatis infection might have a global inhibitory effect on CD8+ T cell activation by coinfecting mice with C. trachomatis and Listeria monocytogenes and we found that the activation of Listeria-specific naive and memory CD8+ T cells was reduced in the presence of C. trachomatis. Together, these results suggest that Chlamydia is able to alter the development of CD8+ T cell responses during both primary and secondary infection, perhaps accounting for the incomplete protection provided by prior Chlamydia infection.     

Detection of serum antibodies to Bartonella henselae and Coxiella burnetii from Japanese children and pregnant women

The participation of Bartonella henselae and Coxiella burnetii in the pathogenesis of fever of unknown origin (FUO) and lymphadenopathy has not been completely clarified. Prevalence of these two agents in Japanese children is also unknown. Serum IgG and IgM antibodies to B. henselae and to C. burnetii were examined by the indirect fluorescence antibody assay. Enzyme immunoassay kits were used to detect serum IgG and IgA antibodies against Chlamydia trachomatis. Out of 200 healthy normal pregnant women, two (1.0%) had serum IgG antibodies to B. henselae, four (2.0%) to C. burnetii and 49 (24.5%) to C. trachomatis. Out of 29 patients with FUO, one (3.4%) had serum IgG antibodies to B. henselae, four (13.8%) to C. burnetii and none to C. trachomatis. Out of 31 patients with cervical lymphadenopathy, three (9.6%) had serum IgG antibodies to B. henselae, two (6.5%) to C. burnetii and none to C. trachomatis. Out of 22 patients with generalized lymphadenopathy, one (4.5%) had serum IgG antibodies to B. henselae, three (13.6%) to C. burnetii and none to C. trachomatis. Prevalences of serum antibodies to C. burnetii in the patients with FUO and generalized lymphadenopathy and to B. henselae in the patients with cervical lymphadenopathy were significantly higher than those of normal pregnant women (Welch's t-test; P<0.01). These two agents may have some roles in the pathogenesis of FUO and lymphadenopathy in Japanese children.     

NALP3炎性体在沙眼衣原体感染中的作用研究进展

沙眼衣原体具有广泛的致病谱,不仅是感染性致盲的首要病因,也是性传播疾病的主要病原体。持续性炎症反应与沙眼衣原体感染致病密切相关。NALP3炎性体是一种细胞内多蛋白复合物,在Ct感染所致的持续炎症反应中发挥重要作用。本文就NALP3炎性体的结构和功能及其在沙眼衣原体感染中的作用作一综述。     

Serological profiling with Chlamycheck, a commercial multiplex recombinant antigen Western blot assay of chlamydial infections

A new chlamydial test system, the Chlamycheck assay, which uses 4 purified recombinant antigens of Chlamydia trachomatis and Chlamydophila pneumoniae and one antigen of Chlamydophila psittaci, has been developed and commercialized. We investigated the reactivities of the recombinant antigens with sera from a group of 30 patients with acute Chlamydia trachomatis infection, 88 patients consulting for sexually transmitted infections, and 46 patients with serological evidence of Chlamydophila pneumoniae infection. The results obtained from human and infected mouse sera suggest that Chlamycheck serology against multiple proteins may provide additional useful information that is not available by conventional whole elementary body microimmunofluorescence or single-antigen enzyme-linked immunosorbent assay serology. Specific serological profiles were associated with acute versus past Chlamydia trachomatis infection or with Chlamydia trachomatis primo-infection versus infection in a Chlamydophila pneumoniae history context.     

衣原体质粒的研究进展

衣原体质粒是一个分子量约为7.5 kb,基因序列高度保守,非整合性的DNA分子,广泛存在于沙眼衣原体的各个血清型中,鼠衣原体和鹦鹉热衣原体也携带该质粒.近年来,人们发现衣原体质粒是一种毒力因子,可以导致小鼠输卵管积水.动物实验显示质粒缺失株可作为减毒活疫苗来预防衣原体感染所致的生殖道和眼睛的病变.不仅如此,衣原体质粒还是一种有效的基因操纵工具,可用于沙眼衣原体致病机制的研究.因此,开展对衣原体质粒的研究具有重要的意义.     

Chlamydia muridarum evades growth restriction by the IFN-gamma-inducible host resistance factor Irgb10

Chlamydiae are obligate intracellular bacterial pathogens that exhibit a broad range of host tropism. Differences in host tropism between Chlamydia species have been linked to host variations in IFN-gamma-mediated immune responses. In mouse cells, IFN-gamma can effectively restrict growth of the human pathogen Chlamydia trachomatis but fails to control growth of the closely related mouse pathogen Chlamydia muridarum. The ability of mouse cells to resist C. trachomatis replication is largely dependent on the induction of a family of IFN-gamma-inducible GTPases called immunity-related GTPases or IRGs. In this study we demonstrate that C. muridarum can specifically evade IRG-mediated host resistance. It has previously been suggested that C. muridarum inactivates the IRG protein Irga6 (Iigp1) to dampen the murine immune response. However, we show that Irga6 is dispensable for the control of C. trachomatis replication. Instead, an effective IFN-gamma response to C. trachomatis requires the IRG proteins Irgm1 (Lrg47), Irgm3 (Igtp), and Irgb10. Ectopic expression of Irgb10 in the absence of IFN-gamma is sufficient to reduce intracellular growth of C. trachomatis but fails to restrict growth of C. muridarum, indicating that C. muridarum can specifically evade Irgb10-driven host responses. Importantly, we find that Irgb10 protein intimately associates with inclusions harboring C. trachomatis but is absent from inclusions formed by C. muridarum. These data suggest that C. muridarum has evolved a mechanism to escape the murine IFN-gamma response by restricting access of Irgb10 and possibly other IRG proteins to the inclusion.     

Interspecies structural diversity among chlamydial genes encoding histone H1.

Recently, a eukaryotic histone H1-like protein has been detected in Chlamydia trachomatis serovar L2 [Hackstadt et al., Proc. Natl. Acad. Sci. USA 88 (1991) 3937-3941; Tao et al., J. Bacteriol. 173 (1991) 2818-2822]. We have cloned the corresponding gene from C. trachomatis serovar J and the Chlamydia psittaci strain mn. Sequencing demonstrated absolute gene identity between the two C. trachomatis serovars L2 and J, but divergence in the C. psittaci strain mn. These differences resulted in altered aa residues (in particular no cysteines) and a smaller molecular mass for H1 from C. psittaci strain mn. The amino acid (aa) sequence comparisons with other histone proteins show best alignment to sea urchin H1, notably in the C terminus, for both C. trachomatis and C. psittaci histones. Chlamydial interspecies aa homology, however, is most conserved at the N terminus, suggestive of a bi-functional role for these unique histone proteins.     

Results of the microbiological, clinical and immunological examination of children with Reiter's disease

Infectious agents were detected in 100% of examined children with Reiter's disease (RD). Chlamydia trachomatis were detected in 98% of cases. In children with RD lesions of joints and eyes often took acute forms with cases of sacroiliitis, early muscular atrophy and conjunctivitis. In 95% of the patients the prostatitis manifestations were detected. In children with RD a rised number of CD lymphocytes in combination with the fivefold rised IL-4 content, an essential increase in the activity of C2-C5 components of the complement and a multiple rised level of PSA were registered.     

Recombination in the ompA gene but not the omcB gene of Chlamydia contributes to serovar-specific differences in tissue tropism, immune surveillance, and persistence of the organism

Sequences of the major outer membrane protein (MOMP) gene (ompA) and the outer membrane complex B protein gene (omcB) from Chlamydia trachomatis, Chlamydia pneumoniae, and Chlamydia psittaci were analyzed for evidence of intragenic recombination and for linkage equilibrium. The Sawyer runs test, compatibility matrices, and index of association analyses provided substantial evidence that there has been a history of intragenic recombination at ompA including one instance of interspecies recombination between the C. trachomatis mouse pneumonitis strain and the C. pneumoniae horse N16 strain. Although none of these methods detected intragenic recombination within omcB, differences in divergence reported in earlier studies suggested that there has been intergenic recombination involving omcB, and the analyses presented in this study are consistent with this. For C. trachomatis, index-of-association analyses suggested a higher degree of recombination for C class than for B class strains and a higher degree of recombination in the downstream half of ompA. In concordance with these findings, many significant breakpoints were found in variable segments 3 and 4 of MOMP for the recombinant strains D/B120, G/UW-57, E/Bour, and LGV-98 identified in this study. We provide examples of how genetic diversity generated by repeated recombination in these regions may be associated with evasion of immune surveillance, serovar-specific differences in tissue tropism, and persistence.     

Chlamydia trachomatis infections in infants.

In recent years considerable progress has been made in understanding chlamydial infections. The spectrum of pediatric Chlamydia trachomatis infection includes neonatal inclusion conjunctivitis, infantile pneumonia, occasional respiratory or genital tract infections in older children and sexually transmitted diseases in adolescents. The role of maternal chlamydial infection in prematurity and in perinatal death is currently an area of active study. We outline the current knowledge of the biologic characteristics of C. trachomatis, the epidemiologic features of chlamydial infection, and the clinical aspects, diagnosis and treatment of neonatal chlamydial infections.     

Detection and frequency of Chlamydia trachomatis DNA in synovial samples from Tunisian patients with reactive arthritis and undifferentiated oligoarthritis

We aimed to determine the frequency of Chlamydia trachomatis DNA in the synovial compartment of 34 arthritic patients. Chlamydia trachomatis DNA was detected using a nested PCR targeting the cryptic plasmid, the 16S rRNA gene and the outer membrane protein 1 gene. The presence of serum immunoglobulin (Ig)G and IgA antibodies against C. trachomatis was studied by a microimmunofluorescence assay and by an enzyme-linked immunosorbent assay, respectively. Synovial samples from 20 of 34 (59%) patients [nine with reactive arthritis (ReA), seven with undifferentiated oligoarthritis (UOA), two with rheumatoid arthritis and two with osteoarthritis] were positive for at least one C. trachomatis DNA sequence by nested PCR. The high sensitivity results most likely from the combination of a standardized automated MagNA Pure extraction method, PCR targeting three different C. trachomatis genes and the screening for C. trachomatis in synovial tissue and fluid samples. There was no correlation between the presence of C. trachomatis DNA in the joint and a Chlamydia -specific serologic response. Our data support that PCR is the method of choice to establish the diagnosis of Chlamydia -induced arthritis in patients with ReA. We suggest that this diagnosis might also be considered in C. trachomatis -positive patients previously classified as UOA.     

Immunology of Chlamydia infection: implications for a Chlamydia trachomatis vaccine

Sexually transmitted Chlamydia trachomatis infections are a serious public-health problem. With more than 90 million new cases occurring annually, C. trachomatis is the most common cause of bacterial sexually transmitted disease worldwide. Recent progress in elucidating the immunobiology of Chlamydia muridarum infection of mice has helped to guide the interpretation of immunological findings in studies of human C. trachomatis infection and has led to the development of a common model of immunity. In this review, we describe our current understanding of the immune response to infection with Chlamydia spp. and how this information is improving the prospects for development of a vaccine against infection with C. trachomatis.     

The 7.5-kb plasmid present in Chlamydia trachomatis is not essential for the growth of this microorganism

An L2 serovar of Chlamydia trachomatis, isolated from a patient with proctocolitis, has been identified that does not contain the common C. trachomatis 7.5-kb plasmid. This isolate was propagated in vitro showing that this plasmid is not required for the growth of C. trachomatis.     

Zinc and Chlamydia trachomatis

Zinc was noted to have significant effects upon the infection of McCoy cells by each of two strains of Chlamydia trachomatis. With a high or low Chlamydia inoculant, the number of infected cells increased up to 200% utilizing supplemental zinc (up to 1 X 10(-4) M) in the inoculation media compared with standard Chlamydia cultivation media (8 X 10(-6) M zinc). Ferric chloride and calcium chloride did not effect any such changes. Higher concentrations of zinc, after 2 hr of incubation with Chlamydia, significantly decreased the number of inclusions. This direct effect of zinc on the Chlamydia remained constant after further repassage of the Chlamydia without supplemental zinc, suggesting a lethal effect of the zinc. Supplemental zinc (up to 10(-4)M) may prove to be a useful addition to inoculation media to increase the yield of culturing for Chlamydia trachomatis. Similarly, topical or oral zinc preparations used by people may alter their susceptivity to Chlamydia trachomatis infections.     

肺炎支原体和沙眼衣原体致儿童急性下呼吸道感染的研究

本文旨在研究儿童社区获得性急性下呼吸道感染(ALRTI)中肺炎支原体(MP)和沙眼衣原体(CT)的感染特征。采用实时荧光定量聚合酶链反应(PCR)检测2006年10月～2008年2月因ALRTI收入复旦大学附属儿科医院的患儿呼吸道标本中MP和CT的DNA,并分析2种病原体感染患儿的临床特征与实验室检查结果。在1312份深部鼻咽分泌物标本中,MP和CT检出率分别为7.85%(103/1312)和2.97%(39/1312)。MP在5岁以上患儿中的检出率为33.33%(30/90),而CT在3个月以内患儿中的检出率为6.28%(31/494)。MP感染后易出现40℃以上高热,较少发生发绀与重症呼吸道感染;白细胞计数常无明显升高,但C反应蛋白升高较多见。CT感染后40℃以上高热和重症呼吸道感染少见,C反应蛋白升高也较少见。结果提示,在5岁以上儿童的社区获得性ALRTI中,MP是重要的病原体;而在3个月以内儿童中,CT为常见病原体之一。     

Chlamydia trachomatis-derived deubiquitinating enzymes in mammalian cells during infection

Chlamydia trachomatis is an obligate intracellular bacterium that causes a variety of diseases in humans. C. trachomatis has a complex developmental cycle that depends on host cells for replication, during which gene expression is tightly regulated. Here we identify two C. trachomatis proteases that possess deubiquitinating and deneddylating activities. We have designated these proteins ChlaDub1 and ChlaDub2. The genes encoding ChlaDub1 and ChlaDub2 are present in all Chlamydia species except for Chlamydia pneumoniae, and their catalytic domains bear similarity to the catalytic domains of other eukaryotic ubiquitin-like proteases (Ulp). The C. trachomatis DUBs react with activity-based probes and hydrolyse ubiquitinated and neddylated substrates. ChlaDub1 and ChlaDub2 represent the first known bacterial DUBs that possess both deubiquitinating and deneddylating activities.     

Low iron availability modulates the course of Chlamydia pneumoniae infection

Chlamydiae are obligate intracellular bacteria residing exclusively in host cell vesicles termed inclusions. We have investigated the effects of deferoxamine mesylate (DAM)-induced iron deficiency on the growth of Chlamydia pneumoniae and Chlamydia trachomatis serovar L2. In epithelial cells subjected to iron starvation and infected with either C. pneumoniae or C. trachomatis L2, small inclusions were formed, and the infectivity of chlamydial progeny was impaired. Moreover, for C. trachomatis L2, we observed a delay in homotypic fusion of inclusions. The inhibitory effects of DAM were reversed by adding exogenous iron-saturated transferrin, which restored the production of infectious chlamydiae. Electron microscopy examination of iron-deprived specimens revealed that the small inclusions contained reduced numbers of C. pneumoniae that were mostly reticulate bodies. We have previously reported specific accumulation of transferrin receptors (TfRs) around C. pneumoniae inclusions within cells grown under normal conditions. Using confocal and electron microscopy, we show here a remarkable increase in the amount of TfRs surrounding the inclusions in iron-starved cultures. It has been shown that iron is an essential factor in the growth and survival of C. trachomatis. Here, we postulate that, for C. pneumoniae also, iron is an indispensable element and that Chlamydia may use iron transport pathways of the host by attracting TfR to the phagosome.     

Evaluation of proposed cytomorphologic criteria for the diagnosis of Chlamydia trachomatis in Papanicolaou smears

To evaluate the proposed cytomorphologic criteria for the cervical cytologic diagnosis of Chlamydia trachomatis infection, a study was made of 171 endocervical smears. All cytomorphologic elements that could be ascribed to Chlamydia trachomatis infection were correlated with the diagnostic confirmation of this microorganism by monoclonal antibody (MAb) staining. The presence of Chlamydia trachomatis was detected in 21 samples (12.28%) by MAb staining. Comparing the cytomorphologic results with the MAb results, the sensitivities and specificities of the Papanicolaou smear diagnoses were 19% and 86% using the cytologic criteria proposed by Gupta and coworkers, 38% and 87% using the criteria proposed by Kiviat and coworkers and 23% and 91% using the criteria proposed by Shiina. In view of (1) its low sensitivity, (2) the subjective elements and individual variations in the proposed cytologic criteria, (3) the similarity with Trichomonas vaginalis-produced exudates and (4) the implications of a misdiagnosis of a sexually transmitted disease, it is concluded that cervical cytology is not useful for ascertaining the presence of Chlamydia trachomatis.     

Antibody-neutralizing activity against all urogenital Chlamydia trachomatis serovars in Chlamydia suis-infected pigs

It is known that neutralizing species-specific or serovar-specific antibodies are produced in response to chlamydial infection in humans and in some animal species. In a previous study, a strong in vitro neutralizing activity to Chlamydia suis in 80% of sera from C. suis-infected pigs had been observed. In view of the close relationship between C. suis and Chlamydia trachomatis, in the present study, the neutralizing activity against D-K C. trachomatis and C. suis purified elementary bodies (EBs) in sera collected from C. trachomatis-infected patients and C. suis-infected pigs was evaluated. A neutralizing activity of 50-70% was observed in the human sera against the homologous serovar and one to five heterologous C. trachomatis serovars. These sera were also able to neutralize C. suis EBs. The pig sera showed a strong neutralizing activity (70-100%) against C. suis EBs and all eight urogenital C. trachomatis serovars. These results suggested the presence of common immunogenic antigens in C. trachomatis and C. suis. Immunoblot analysis, performed to elucidate the target of this neutralizing activity, showed a clear reactivity in human and pig sera against two proteins of 150 and 40 kDa MW, when tested either with C. trachomatis or with C. suis EBs.