Dramatic Changes in Malaria Population Genetic Complexity in Dielmo and Ndiop, Senegal, Revealed Using Genomic Surveillance

Abstract

Dramatic changes in transmission intensity can impact Plasmodium population diversity. Using samples from 2 distant time-points in the Dielmo/Ndiop longitudinal cohorts from Senegal, we applied a molecular barcode tool to detect changes in parasite genotypes and complexity of infection that corresponded to changes in transmission intensity. We observed a striking statistically significant difference in genetic diversity between the 2 parasite populations. Furthermore, we identified a genotype in Dielmo and Ndiop previously observed in Thiès, potentially implicating imported malaria. This genetic surveillance study validates the molecular barcode as a tool to assess parasite population diversity changes and track parasite genotypes.

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Evidence for Viral Interference and Cross-reactive Protective Immunity Between Influenza B Virus Lineages

Abstract

Background

Two influenza B virus lineages, B/Victoria and B/Yamagata, cocirculate in the human population. While the lineages are serologically distinct, cross-reactive responses to both lineages have been detected. Viral interference describes the situation whereby infection with one virus limits infection and replication of a second virus. We investigated the potential for viral interference between the influenza B virus lineages.

Methods

Ferrets were infected and then challenged 3, 10, or 28 days later with pairs of influenza B/Victoria and B/Yamagata viruses.

Results

Viral interference occurred at challenge intervals of 3 and 10 days and occasionally at 28 days. At the longer interval, shedding of challenge virus was reduced, and this correlated with cross-reactive interferon γ responses from lymph nodes from virus-infected animals. Viruses from both lineages could prevent or significantly limit subsequent infection with a virus from the other lineage. Coinfections were rare, indicating the potential for reassortment between lineages is limited.

Conclusions

These data suggest that innate and cross-reactive immunity mediate viral interference and that this may contribute to the dominance of a specific influenza B virus lineage in any given influenza season. Furthermore, infection with one influenza B virus lineage may be beneficial in protecting against subsequent infection with either influenza B virus lineage.

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Role of PCSK9 in the Development of Mouse Periodontitis Before and After Treatment: A Double-Edged Sword

Abstract

Periodontitis is a highly prevalent infectious disease associated genetically with coronary heart disease (CHD). The effects of proprotein convertase subtilisin/kexin type 9 (PCSK9), a critical regulator of CHD, on periodontitis have not been studied to date. Here, we found that PCSK9 expression was increased in periodontitis patients and Porphyromonas gingivalis (Pg)–infected mice. Loss of PCSK9 attenuated Pg-induced periodontal bone loss in mice. First, PCSK9 deficiency reduced the release of inflammation-associated cytokines, such as tumor necrosis factor alpha (TNF-α) and interleukin 1β, in vitro and in vivo. Second, its deficiency enhanced Pg and endotoxin clearance during Pg invasion in part by upregulating CD36 and low-density lipoprotein receptor (LDLR), respectively. However, after berberine treatment, periodontal bone regeneration in the PCSK9 knockout group was significantly lower than that in wild-type. This was because PCSK9 overexpression promoted osteogenic differentiation of periodontal ligament stem cells (PDLCs) prechallenged by TNF-α. Furthermore, PCSK9 could rescue PDLC osteogenesis by repressing the NF-κB signaling pathway by interacting with TRAF2. These results suggest that PCSK9 may be a potent drug target for treating periodontitis.

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Impact of the Levonorgestrel-Releasing Intrauterine System on the Progression of Chlamydia trachomatis Infection to Pelvic Inflammatory Disease in a Baboon Model

Abstract

Background

Understanding the relationship between the levonorgestrel (LNG)–releasing intrauterine system (IUS) and sexually transmitted infections (STIs) is increasingly important as use of the LNG-IUS grows to include women at higher risk for STIs. This study assessed the impact of the LNG-IUS on development of Chlamydia trachomatis pelvic inflammatory disease, using a baboon model.

Methods

Baboons with and those without the LNG-IUS were cervically inoculated with C. trachomatis and monitored daily, and cervical and fallopian tube swab specimens were collected weekly for C. trachomatis quantitation by nucleic acid amplification testing and culture. Vaginal swab specimens were collected for cytokine analysis, and serum samples were obtained for detection of C. trachomatis antibodies.

Results

The LNG-IUS resulted in an increased C. trachomatis burden in the cervix, with the bacterial burden in the LNG-IUS group diverging from that in the non–LNG-IUS group by 6 weeks after infection. One of 7 baboons in the non–LNG-IUS group and 2 of 6 in the LNG-IUS group developed pelvic inflammatory disease, while 3 animals in each group met criteria suggestive of pelvic inflammatory disease. LNG-IUS increased baseline interleukin 8 levels but failed to further upregulate interleukin 8 during infection. In LNG-IUS recipients, early perturbations in the interleukin 1β axis corresponded to decreased C. trachomatis clearance and increased T-helper type 2 immune responses.

Conclusion

LNG-IUS use results in delayed clearance of C. trachomatis and might alter the reproductive tract immune environment.

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Polymorphisms in the Wilms Tumor Gene Are Associated With Interindividual Variations in Rubella Virus–Specific Cellular Immunity After Measles-Mumps-Rubella II Vaccination

Abstract

Rubella vaccination induces widely variable immune responses in vaccine recipients. While rubella vaccination is effective at inducing immunity to rubella infection in most subjects, up to 5% of individuals do not achieve or maintain long-term protective immunity. To expand upon our previous work identifying genetic polymorphisms that are associated with these interindividual differences in humoral immunity to rubella virus, we performed a genome-wide association study in a large cohort of 1843 subjects to discover single-nucleotide polymorphisms (SNPs) associated with rubella virus–specific cellular immune responses. We identified SNPs in the Wilms tumor protein gene (WT1) that were significantly associated (P < 5 × 10^–8) with interindividual variations in rubella-specific interleukin 6 secretion from subjects’ peripheral blood mononuclear cells postvaccination. No SNPs were found to be significantly associated with variations in rubella-specific interferon-γ secretion. Our findings demonstrate that genetic polymorphisms in the WT1 gene in subjects of European ancestry are associated with interindividual differences in rubella virus–specific cellular immunity after measles-mumps-rubella II vaccination.

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Analysis of Memory B-Cell Responses Reveals Suboptimal Dosing Schedule of a Licensed Vaccine

Abstract

Current guidance recommends that adolescents receive a 2-dose human papillomavirus (HPV) vaccine, whereas young adults and immunocompromised persons receive 3 doses. We examined secondary responses of vaccine-elicited memory B cells (Bmem) in naive women receiving 3 doses of the quadrivalent HPV vaccine to understand the quality of B-cell memory generated by this highly effective vaccine. Unexpectedly, we observed a lower Bmem response rate and magnitude of Bmem responses to the third dose than to a booster dose administered at month 24. Moreover, high titers of antigen-specific serum antibody at vaccination inversely correlated with Bmem responses. As the purpose of additional doses/boosters is to stimulate Bmem to rapidly boost antibody levels, these results indicate the timing of the third dose is suboptimal and lend support to a 2-dose HPV vaccine for young adults. Our findings also indicate more broadly that multidose vaccine schedules should be rationally determined on the basis of Bmem responses.

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Protection of the Human Gut Microbiome From Antibiotics

Abstract

Background

Antibiotics are life-saving drugs but severely affect the gut microbiome with short-term consequences including diarrhea and selection of antibiotic-resistant bacteria. Long-term links to allergy and obesity are also suggested. We devised a product, DAV132, and previously showed its ability to deliver a powerful adsorbent, activated charcoal, in the late ileum of human volunteers.

Methods

We performed a randomized controlled trial in 28 human volunteers treated with a 5-day clinical regimen of the fluoroquinolone antibiotic moxifloxacin in 2 parallel groups, with or without DAV132 coadministration. Two control goups of 8 volunteers each receiving DAV132 alone, or a nonactive substitute, were added.

Results

The coadministration of DAV132 decreased free moxifloxacin fecal concentrations by 99%, while plasmatic levels were unaffected. Shotgun quantitative metagenomics showed that the richness and composition of the intestinal microbiota were largely preserved in subjects co-treated with DAV132 in addition to moxifloxacin. No adverse effect was observed. In addition, DAV132 efficiently adsorbed a wide range of clinically relevant antibiotics ex vivo.

Conclusions

DAV132 was highly effective to protect the gut microbiome of moxifloxacin-treated healthy volunteers and may constitute a clinical breakthrough by preventing adverse health consequences of a wide range of antibiotic treatments.

Clinical Trials Registration

NCT02176005.

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