Route of Vaccine Administration Influences the Impact of Fms-Like Tyrosine Kinase 3 Ligand (Flt3L) on Chlamydial-Specific Protective Immune Responses.

We tested the hypothesis that the impact of the Fms-like tyrosine kinase 3-ligand (Flt3L; FL) on recombinant Vibrio cholerae ghost (rVCG) vaccine-induced chlamydial immunity is influenced by route of vaccine delivery. Female C57BL/6J mice were immunized rectally (IR) or intramuscularly (IM) with rVCG co-expressing the Chlamydia trachomatis PmpD and PorB proteins (rVCG- PmpD/PorB) with and without FL or glycoprotein D of HSV-2 (rVCG-gD2) as antigen control. Vaccine evaluation was based on measurement of T cell proliferation, Th1/Th2 cytokine, and humoral responses at systemic and mucosal compartments, and protection against intravaginal challenge infection. Results revealed that high levels of CD4+ T cell-mediated and humoral immune responses, were elicited in mice as a function of both IR and IM immunization. Unexpectedly, co-administration of vaccine with FL enhanced specific Th1-type cytokine levels and T cell proliferative responses following IR but not IM immunization. While administration of vaccine with FL enhanced the specific mucosal and systemic IgA antibody responses following both immunization routes, IgG2c responses were not enhanced following IR delivery. The vaccine-induced immune effectors protected mice against live heterologous C. muridarum infection irrespective of route of vaccine administration, with the regimen incorporating FL having a protective advantage. Further evaluation showed that protection afforded by the FL adjuvanted vaccine was facilitated by CD4+ T cells, as indicated by reduction in the intensity and duration of genital chlamydial shedding by naïve mice following adoptive transfer of immune CD4+ T cells. Taken together, the results indicate that comparable protective immunity, which is enhanced by co-delivery with FL, is elicited in the female genital tract against Chlamydia infection after mucosal and systemic administration, highlighting the ability of FL to function as an effective immunostimulator at both mucosal and systemic sites. The differential modulation of humoral and cellular immune responses, and protective immunity afforded by the FL adjuvanted vaccine following IR administration indicates that the immunomodulatory impact of FL on chlamydial-specific immunity is influenced by the route of vaccine administration. Thus, targeting of VCG-based vaccines to antigen presenting cells by co-delivery with FL is a feasible immunization approach for inducing effective chlamydial immunity in the female genital tract.

Epidemiología y control actual de las infecciones de transmisión sexual. Papel de las unidades de ITS / Epidemiology and current control of sexually transmitted infections. The role of STI clinics

La carga de enfermedad derivada de las infecciones de transmisión sexual (ITS) compromete la salud sexual, reproductiva y del recién nacido. La presencia de unas ITS facilita la transmisión de otras, como el VIH, y provoca cambios celulares que preceden algunos tipos de cáncer. Todo ello hace de las ITS un problema de salud pública de primer orden no controlado. En España, la infección gonocócica sigue creciendo desde el inicio de la década del 2000, mientras que la sífilis se mantiene estable en unos niveles altos desde el 2011. Ambas son más frecuentes en varones. Chlamydia trachomatis es la ITS más prevalente, afectando principalmente a mujeres de 20-24 años. Las unidades de ITS son el instrumento fundamental para abordar este problema. Tratan con poblaciones especialmente vulnerables a estas infecciones y son esenciales para su control mediante intervenciones que disminuyen la eficiencia de su transmisión y la duración de la infectividad. Además, son la principal fuente del conocimiento epidemiológico de las mismas

The burden of disease from sexually transmitted infections (STI) undermines sexual and reproductive health and the health of newborn infants. The presence of some STI facilitates the transmission of others, such as HIV, and cause cellular changes that precede some types of cancer. For all these reasons STIs are a first order uncontrolled public health problem. In Spain, gonococcal infection has been on rising since the beginning of 2000, while syphilis has remained stable at high levels since 2011. Both infections are more common in males. Chlamydia trachomatis is the most common STI, and principally affects females between the ages of of 20 and 40. STI units are an essential instrument to tackle this problem. They deal with populations that are particularly vulnerable to these infections and are essential for their control by means of interventions that reduce their transmission efficiency and infectivity duration. They are also the principal source of epidemiological information about these infections

Protocolo del Sistema Nacional de Vigilancia Epidemiológica de transmisión sexual y VIH/VIH avanzado. No. 07 / Protocol of the National Epidemiological Surveillance System for sexual transmission and advanced HIV / HIV. No. 07

Estos protocolos están dirigido a personal médico, paramédico y otros profesionales que realizan acciones gerenciales y operativas de vigilancia epidemiológica en los servicios de salud del país, y están divididos en varios tomos para dar a conocer y actualizar la identificación y medidas de control para diversos padecimientos a fin de continuar con el mejoramiento de las capacidades técnicas de los trabajadores de salud, que permita planificar la prestación de servicios con decisiones partiendo de un enfoque epidemiológico comprobado, para responder a los cambios de tendencias epidemiológicas y con ello contribuir al fortalecimiento de prácticas asertivas de la salud pública de nuestro país. En el presente protocolo se incluirán tres elementos: La vigilancia en poblaciones clave será centinela Se instituirá la vigilancia para la población general a través de Epiweb La vigilancia de la mujer embarazada para la prevención y eliminación de la transmisión materno infantil de la sífilis congénita, a través de Epiweb

Protection against genital tract Chlamydia trachomatis infection following intranasal immunization with a novel recombinant MOMP VS2/4 antigen.

The asymptomatic nature of most Chlamydia trachomatis infections and the lack of appropriate effects by current prevention and management call for vaccine development. We evaluated a recombinant subunit vaccine candidate based on the major outer membrane protein variable segments 2 and 4 (MOMP VS2/4). To achieve maximal immunogenicity and ease of production and purification, MOMP VS2/4 was constructed by using highly immunogenic sequences of MOMP only, thereby minimizing the presence of hydrophobic regions, and spacing the immunogenic epitopes with a flexible amino acid sequence. A purification tag was also added. The MOMP VS2/4 was given intranasally, with or without intravaginal boost, with cholera toxin (CT) adjuvant to C57BL/6 mice, which were screened for immunogenicity and protection against a live challenge infection with C. trachomatis serovar D. Bacterial shedding, cell-mediated responses, and antibody responses were monitored. Immunized mice exhibited significantly less bacterial shedding and were better protected against infertility as compared to unimmunized control mice. Immunizations stimulated both systemic and local specific antibody (IgG1, IgG2c, and IgA) responses, and primed T cells that produced interferon-γ and interleukins 13 and 17 upon challenge with recall antigen. Thus, MOMP VS2/4, in combination with CT adjuvant, stimulated Th1, Th2, and Th17 effector cells, and generated protective immunity associated with less pathology. We regard MOMP VS2/4 as a promising candidate for further development into a mucosal chlamydial vaccine.

2013 European guideline on the management of lymphogranuloma venereum.

WHAT IS NEW IN THIS UPDATED GUIDELINE?: This is the update version of the 2010 European guideline on the management of lymphogranuloma venereum (LGV). New issues are: EPIDEMIOLOGY: Based on clonal relatedness of prevalent LGV strains there is evidence that the LGV epidemic among men who have sex with men (MSM) in the Western world prevailed already in the United States in the 1980s and was introduced into Europe by the end of the last century. AETIOLOGY AND TRANSMISSION: A new LGV variant causing severe proctitis was unveiled and designated L2c. The L2b LGV variant causing the vast majority of infections among MSM is now also found among a few heterosexual women. MANAGEMENT: Apart from HIV and STI screening, Hepatitis C Virus (HCV) testing should be offered to all LGV patients. To exclude reinfections, STI screening during a follow-up visit 3 months after an LGV diagnosis should be offered.

Seroprevalence of antibodies against Pkn1, a novel potential immunogen, in Chlamydia trachomatis-infected Macaca nemestrina and human patients.

Chlamydia trachomatis (CT) is an important cause of sexually transmitted genital tract infections (STIs) and trachoma. Despite major research into chlamydial pathogenesis and host immune responses, immunoprotection has been hampered by the incomplete understanding of protective immunity in the genital tract. Characterized vaccine candidates have shown variable efficacy ranging from no protection to partial protection in vivo. It is therefore a research priority to identify novel chlamydial antigens that may elicit protective immune responses against CT infection. In the present study we assessed the seroprevalence of antibodies against protein kinase1 (Pkn1), DNA ligaseA (LigA), and major outer membrane protein A (OmpA) following natural CT infection in humans and in experimentally induced CT infection in Macaca nemestrina. Antigenic stretches of Pkn1, LigA, and OmpA were identified using bioinformatic tools. Pkn1, LigA, and OmpA genes were cloned in bacterial expression vector and purified by affinity chromatography. Our results demonstrate significantly high seroprevalence of antibodies against purified Pkn1 and OmpA in sera obtained from the macaque animal model and human patients infected with CT. In contrast no significant seroreactivity was observed for LigA. The seroprevalence of antibodies against Pkn1 suggest that nonsurface chlamydial proteins could also be important for developing vaccines for C. trachomatis.

Genital Chlamydia trachomatis: understanding the roles of innate and adaptive immunity in vaccine research.

Chlamydia trachomatis is the leading cause of bacterial sexually transmitted disease worldwide, and despite significant advances in chlamydial research, a prophylactic vaccine has yet to be developed. This Gram-negative obligate intracellular bacterium, which often causes asymptomatic infection, may cause pelvic inflammatory disease (PID), ectopic pregnancies, scarring of the fallopian tubes, miscarriage, and infertility when left untreated. In the genital tract, Chlamydia trachomatis infects primarily epithelial cells and requires Th1 immunity for optimal clearance. This review first focuses on the immune cells important in a chlamydial infection. Second, we summarize the research and challenges associated with developing a chlamydial vaccine that elicits a protective Th1-mediated immune response without inducing adverse immunopathologies.

Hepatitis B virus surface antigen as delivery vector can enhance Chlamydia trachomatis MOMP multi-epitope immune response in mice.

Chlamydia trachomatis is the leading cause of sexually transmitted infections worldwide. There is currently no commercially available vaccine against C. trachomatis. Major outer membrane protein (MOMP) of C. trachomatis is considered to be an ideal candidate for prophylactic vaccine. We designed a MOMP multi-epitope containing T- and B-cell epitope-rich peptides and developed hepatitis B surface antigen (HBsAg) as antigen delivery vehicle. In order to study the immunogenicity and efficacy of the candidate vaccine in a murine model of chlamydial genital infection, we engineered a recombinant plasmid expressing HBsAg and MOMP multi-epitope genes. Results of reverse transcription polymerase chain reaction and immunofluorescence assay revealed successful expression of the recombinant HBsAg/MOMP multi-epitope gene at both the transcription and translation levels. Intramuscular administration in mice was able to elicit not only antibodies against Chlamydia and HBsAg but also cytotoxic T lymphocyte activity against Chlamydia. In addition, mice inoculated with the rHBsAg were highly resistant to C. trachomatis genital infection. The rHBsAg DNA with MOMP multi-epitope appended at the C terminus of the HBsAg stimulated a stronger immune response and protective response than that appended at the N terminus. Together, our results suggested that use of a recombinant HBsAg encoding the MOMP multi-epitope could be a powerful approach to developing a safe and immunogenic C. trachomatis vaccine.

Urethral lymphogranuloma venereum infections in men with anorectal lymphogranuloma venereum and their partners: the missing link in the current epidemic?

Urethral lymphogranuloma venereum (LGV) is not screened routinely. We found that in 341 men having sex with men with anorectal LGV, 7 (2.1%) had concurrent urethral LGV. Among 59 partners, 4 (6.8%) had urethral LGV infections. Urethral LGV is common, probably key in transmission, and missed in current routine LGV screening algorithms.

[Current epidemiology of bacterial STIs in France]. / Épidémiologie actuelle des infections sexuellement transmissibles bactériennes en France.

Sexually transmitted infections (STIs) remains a major problem of public health in France. Voluntary networks of physicians (RésIST) and laboratories (Rénago, Rénachla, lymphogranuloma venereum: LGV network) produce indicators showing the evolution of the main bacterial STIs. In 2010, the main findings were the following. The number of gonococcal infections has increased throughout the decade 2000 to 2010. The decrease in susceptibility of gonococcal strains to first-line antibiotics (extended-spectrum cephalosporins) needs to keep great attention. The number of screening and diagnosis of chlamydial urogenital infections also continues to rise in both sexes, particularly due to increased screening among young people. The relatively stable number of cases of early syphilis and of rectal LGV needs to be confirmed over the coming years. Both of these STIs affect overwhelmingly homo/bisexual men. There is still a high level of HIV co-infection with LGV and syphilis, and to a lesser extent with gonorrhea. We observe that condom use is still inadequate, especially during oral sex.

Condom effectiveness against non-viral sexually transmitted infections: a prospective study using electronic daily diaries.

OBJECTIVES: To prospectively evaluate the protective value of consistent and correct use of latex condoms against the acquisition of Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis. METHODS: Patients (N=929) attending clinics that treat sexually transmitted infections (STIs) were prospectively followed for up to 6 months. Urine STI nucleic acid amplification testing was performed at baseline, 3 months and 6 months. Participants were instructed to respond to daily prompts from a handheld device by completing a report for each penile-vaginal sexual intercourse event. Generalised estimating equation models examined associations of consistent as well as consistent and correct condom use with STI incidence over 3-month intervals. RESULTS: Consistent condom use was not significantly associated with STI incidence (Estimated OR (EOR)=0.75; 95% CI (CI) 0.43 to 1.30; p=0.31). However, individuals who used condoms both correctly and consistently were estimated to have 59% lower odds of acquiring an STI (EOR=0.41; 95% CI  0.19 to 0.90; p=.026), compared to those who did not. CONCLUSIONS: The correct as well as the consistent use of condoms greatly reduces the odds of non-viral STI acquisition.

Facilitating chlamydia testing among young people: a randomised controlled trial in cyberspace.

OBJECTIVES: Chlamydia notifications have been rising in Australia for over a decade and are highest in young people. This study aimed to evaluate the impact of an internet-based intervention on chlamydia testing among young people 16-25 years. METHODS: In this randomised controlled trial, recruitment, data collection, study interventions and follow-up occurred entirely in cyberspace, facilitated by a website. Eligible participants were aged 16-25 years and resided in Australia. The intervention group received personalised emails inviting interaction about chlamydia testing, while the control group received regular impersonal emails. Primary outcome was self-reported chlamydia testing at 6-month follow-up; secondary outcomes were condom use and changes in knowledge and attitudes. RESULTS: 704 young people completed baseline information, 40 were excluded and five withdrew prior to follow-up. The follow-up rate was 47.3% overall. In the intervention group, 40.6% (95% CI 30.7% to 51.1%) reported having had a chlamydia test at follow-up compared with 31.0% (95% CI 24.8% to 37.2%) in the control group (p=0.07). A per-protocol analysis found that those who engaged in email interaction were more likely to report chlamydia test uptake compared with those in the control group (52.5%, 95% CI 39.3 to 65.4% cf 31.0%, 95% CI 24.8% to 37.2%, p=0.002). There were no differences in secondary outcomes between groups. CONCLUSIONS: This is the first randomised controlled trial undertaken in cyberspace to promote chlamydia testing. E-technology may be useful in promoting chlamydia testing and healthcare seeking behaviour in young people.

Protection of pigs against genital Chlamydia trachomatis challenge by parenteral or mucosal DNA immunization.

The current study evaluates combined aerosol-vaginal delivery of a MOMP-based Chlamydia trachomatis (serovar E) DNA vaccine in a pig genital challenge model. Most non-replicating antigens are rather poor mucosal immunogens in comparison to replicating antigens. Therefore, a mucosal administered DNA vaccine, which actually mimics a live vaccine, could be promising. Protection was promoted by plasmids encoding the porcine granulocyte macrophage-colony stimulating factor (pcDNA3.1zeo::GM-CSF), the Escherichia coli thermo-labile enterotoxin (LT) subunit A (plasmid PJV2004::LTa) and subunit B (plasmid PJV2005::LTb). Mucosal C. trachomatis DNA vaccination induced significant protection against genital C. trachomatis challenge although the infection could not be eradicated. Intradermal immunization was significantly less efficient in protecting experimentally infected pigs. Protection was correlated with efficient T cell priming and significantly higher serum IgA titers following primo vaccination.

Lymphogranuloma venereum: a hidden emerging problem, Barcelona, 2011.

From the beginning of 2007 until the end of 2011, 146 cases of lymphogranuloma venereum (LGV) were notified to the Barcelona Public Health Agency. Some 49% of them were diagnosed and reported in 2011, mainly in men who have sex with men. Almost half of them, 32 cases, were reported between July and September. This cluster represents the largest since 2004. This article presents the ongoing outbreak of LGV in Barcelona.

Protective immunity against Chlamydia trachomatis genital infection induced by a vaccine based on the major outer membrane multi-epitope human papillomavirus major capsid protein L1.

The administration of an efficacious vaccine is the most effective long-term measure to control the genital tract infection caused by Chlamydia trachomatis (Ct) in humans. The current challenge for Ct vaccine development is to develop an effective delivery vehicle for induction of a high level of mucosal T and complementary B cell responses. We evaluated the immunogenicity and efficacy of a candidate vaccine comprising the major outer membrane protein (MOMP) multiepitope of Ct delivered with the human papillomavirus (HPV) major capsid protein L1 as a vehicle with adjuvant properties, in a murine model of chlamydial genital infection. A recombinant plasmid pcDNA3.1(+) containing mammalian codon-optimization HPV6b L1 gene and Ct MOMP multiepitope was constructed. The Ct MOMP multiepitope containing T- and B-cell epitope-rich peptides was inserted into C-terminal of HPV6b L1-coding sequence. The constructed plasmid after verified by enzyme restriction assay and DNA sequencing was transfected into COS-7 cells. Expression of the chimeric gene in COS-7 cells was confirmed by RT-PCR, Western blot analysis and immunofluorescence assay. Results revealed successful expression of the chimeric HPV6b L1/Ct MOMP multiepitope gene both at the mRNA and protein levels in transfected COS-7 cells. Intramuscular (IM) administration in mice was able to elicit not only antibodies against Ct MOMP, but also Th1 and cytotoxic T lymphocyte activity against the Ct MOMP epitopes. In addition, recipients of IM immunization of HPV6b L1/Ct MOMP multiepitope were highly resistant to infection. Altogether, the results suggested that IM delivery of HPV6b L1-MOMP multiepitope may be a suitable vaccine regimen potentially capable of inducing protective mucosal immunity against Ct infection.

Validation of the Chlamydia trachomatis genital challenge pig model for testing recombinant protein vaccines.

Chlamydia trachomatis is a Gram-negative obligate intracellular bacterial pathogen that is the leading cause of bacterial sexually transmitted disease in humans in developing countries. A vaccination programme is considered to be the best approach to reduce the prevalence of C. trachomatis infections. However, there are still no commercial C. trachomatis vaccines. In order to develop effective C. trachomatis vaccines, it is important to identify those antigens that elicit a protective immune response, and to develop new and adequate methods and adjuvants for effective vaccine delivery, as conventional methods have failed to induce protective immunity. In order to test different vaccine candidates, animal models are needed. Former studies have used non-primate monkeys, mice or guinea pig infection models. The present study used a pig model for testing recombinant protein vaccines. Two recombinant proteins, polymorphic membrane protein G (PmpG), and secretion and cellular translocation protein C (SctC), were tested for their ability to create protection in a pig C. trachomatis challenge model. The vaccines were administered subcutaneously with GNE adjuvant. Six weeks later, animals were challenged intravaginally with C. trachomatis serovar E. After a further 4 weeks, the pigs were euthanized. PmpG-immunized pigs were better protected than pigs immunized with the less promising SctC candidate vaccine antigen. Interestingly, significant protection was apparently not correlated with a strong humoral immune response upon subcutaneous immunization. In conclusion, the pig model is useful for studying the efficacy of vaccine candidates against genital human C. trachomatis infection.

Immunity and vaccines against sexually transmitted Chlamydia trachomatis infection.

PURPOSE OF REVIEW: The aim is to review recent findings on immunity and vaccine development to Chlamydia trachomatis. RECENT FINDINGS: There is increasing knowledge on the interactions between C. trachomatis and infected host cells. During genital infection the organism avoids generating protective immunity but immune responses to a number of chlamydial proteins have been associated with reproductive tract pathology. Various vaccine and adjuvant preparations have been tried experimentally. Information generated by proteomics and complex studies of serological and T-lymphocyte immune responses points to novel vaccine candidates. SUMMARY: C. trachomatis, an obligate intracellular bacterium, is the commonest sexually transmitted infection worldwide and is associated with reproductive pathology. To develop rational vaccines it is necessary to understand the complex lifecycle of the organism, the host immune response to infection and how these relate to disease. Infection does not prevent re-infection and antibiotic treatment prevents antibody production at a population level. It remains unclear what type of immune response would be sufficient to prevent infection and/or re-infection. Although the prevalence and demographics of infection and the severity of disease associations suggest that it would be desirable, there is no vaccine currently available. A number of studies have identified novel vaccine candidates.