Neisseria gonorrhoeae (the gonococcus, Gc) causes the sexually transmitted infection gonorrhea. Gc is a prominent threat to human health by causing severe lifelong sequelae, including infertility and ...chronic pelvic pain, which is amplified by the emergence of “superbug” strains resistant to all current antibiotics. Gc is highly adapted to colonize human mucosal surfaces, where it survives despite initiating a robust inflammatory response and influx of polymorphonuclear leukocytes (PMNs, neutrophils) that typically clear bacteria. Here, dual-species RNA-sequencing was used to define Gc and PMN transcriptional profiles alone and after infection. Core host and bacterial responses were assessed for two strains of Gc and three human donors’ PMNs. Comparative analysis of Gc transcripts revealed overlap between Gc responses to PMNs, iron, and hydrogen peroxide; 98 transcripts were differentially expressed across both Gc strains in response to PMN co-culture, including iron-responsive and oxidative stress response genes. We experimentally determined that the iron-dependent TbpB is suppressed by PMN co-culture, and iron-limited Gc have a survival advantage when cultured with PMNs. Analysis of PMN transcripts modulated by Gc infection revealed differential expression of genes driving cell adhesion, migration, inflammatory responses, and inflammation resolution pathways. Production of pro-inflammatory cytokines, including IL1B and IL8, the adhesion factor ICAM1, and prostaglandin PGE2 were induced in PMNs in response to Gc. Together, this study represents a comprehensive and experimentally validated dual-species transcriptomic analysis of two isolates of Gc and primary human PMNs that gives insight into how this bacterium survives innate immune onslaught to cause disease.
The bacterial pathogen
is an urgent global health problem due to increasing numbers of infections, coupled with rampant antibiotic resistance. Vaccines against gonorrhea are being prioritized to ...combat drug-resistant
. Meningococcal serogroup B vaccines such as four-component meningococcal B vaccine (4CMenB) are predicted by epidemiology studies to cross-protect individuals from natural infection with
and elicit antibodies that cross-react with
. Evaluation of vaccine candidates for gonorrhea requires a suite of assays for predicting efficacy
and in animal models of infection, including the role of antibodies elicited by immunization. Here, we present the development and optimization of assays to evaluate antibody functionality after immunization of mice: antibody binding to intact
, serum bactericidal activity, and opsonophagocytic killing activity using primary human neutrophils polymorphonuclear leukocytes (PMNs). These assays were developed with purified antibodies against
and used to evaluate serum from mice that were vaccinated with 4CMenB or given alum as a negative control. Results from these assays will help prioritize gonorrhea vaccine candidates for advanced preclinical to early clinical studies and will contribute to identifying correlates and mechanisms of immune protection against
.
Summary
Motile bacteria are proficient at finding optimal environments for colonization. Often, they use chemotaxis to sense nutrient availability and dangerous concentrations of toxic chemicals. For ...many bacteria, the repertoire of chemoreceptors is large, suggesting they possess a broad palate with respect to sensing. However, knowledge of the molecules detected by chemotaxis signal transduction systems is limited. Some bacteria, like Vibrio parahaemolyticus, are social and swarm in groups on surfaces. This marine bacterium and human pathogen secretes the S signal autoinducer, which cues degradation of intracellular c‐di‐GMP leading to transcription of the swarming program. Here, we report that the S signal also directs motility at a behavioral level by serving as a chemoattractant. The data demonstrate that V. parahaemolyticus senses the S signal using SscL and SscS, homologous methyl‐accepting chemotaxis proteins. SscL is required by planktonic bacteria for S signal chemotaxis. SscS plays a role during swarming, and mutants lacking this chemoreceptor swarm faster and produce colonies with more deeply branched swarming fronts than the wild type or the sscL mutant. Other Vibrio species can swim toward the S signal, suggesting a recruitment role for this cell‐cell communication molecule in the context of polymicrobial marine communities.
Bacteria can be social and move in groups. Here, we show that Vibrio parahaemolyticus coordinates motility using the S signal, a cell‐cell signaling molecule that serves as a chemoattractant during swimming and swarming. Two methyl‐accepting chemoreceptors detect this autoinducer. One is necessary for S signal reception by liquid‐grown bacteria, while the other is important for chemotaxis by surface‐grown bacteria. Other Vibrio species respond to the S signal, suggesting a role for recruitment in polymicrobial communities.
B.1.351 is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant most resistant to antibody neutralization. We demonstrate how the dose and number of immunizations influence ...protection. Nonhuman primates received two doses of 30 or 100 µg of Moderna's mRNA-1273 vaccine, a single immunization of 30 µg, or no vaccine. Two doses of 100 µg of mRNA-1273 induced 50% inhibitory reciprocal serum dilution neutralizing antibody titers against live SARS-CoV-2 p.Asp614Gly and B.1.351 of 3,300 and 240, respectively. Higher neutralizing responses against B.1.617.2 were also observed after two doses compared to a single dose. After challenge with B.1.351, there was ~4- to 5-log
reduction of viral subgenomic RNA and low to undetectable replication in bronchoalveolar lavages in the two-dose vaccine groups, with a 1-log
reduction in nasal swabs in the 100-µg group. These data establish that a two-dose regimen of mRNA-1273 will be critical for providing upper and lower airway protection against major variants of concern.
Abstract Purpose To evaluate gut microbiome in relation to recent high-intensity sweetener consumption in healthy adults. Methods Thirty-one adults completed a four-day food record and provided a ...fecal sample on the fifth day. Bacterial community in the samples was analyzed using multitag pyrosequencing. Across consumers and nonconsumers of aspartame and acesulfame-K, bacterial abundance was compared using nonparametric statistics, and bacterial diversity was compared using UniFrac analysis. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) was used to predict mean relative abundance of gene function. Results There were seven aspartame consumers and seven acesulfame-K consumers. Three individuals overlapped groups, consuming both sweeteners. There were no differences in median bacterial abundance (class or order) across consumers and nonconsumers of either sweetener. Overall bacterial diversity was different across nonconsumers and consumers of aspartame ( P < .01) and acesulfame-K ( P = .03). Mean predicted gene abundance did not differ across consumers and nonconsumers of aspartame or acesulfame-K. Conclusions Bacterial abundance profiles and predicted gene function were not associated with recent dietary high-intensity sweetener consumption. However, bacterial diversity differed across consumers and nonconsumers. Given the increasing consumption of sweeteners and the role that the microbiome may have in chronic disease outcomes, work in further studies is warranted.
Immune correlates of protection can be used as surrogate endpoints for vaccine efficacy. Here, nonhuman primates (NHPs) received either no vaccine or doses ranging from 0.3 to 100 μg of the mRNA-1273 ...severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine. mRNA-1273 vaccination elicited circulating and mucosal antibody responses in a dose-dependent manner. Viral replication was significantly reduced in bronchoalveolar lavages and nasal swabs after SARS-CoV-2 challenge in vaccinated animals and most strongly correlated with levels of anti–S antibody and neutralizing activity. Lower antibody levels were needed for reduction of viral replication in the lower airway than in the upper airway. Passive transfer of mRNA-1273–induced immunoglobulin G to naïve hamsters was sufficient to mediate protection. Thus, mRNA-1273 vaccine–induced humoral immune responses are a mechanistic correlate of protection against SARS-CoV-2 in NHPs.
Neutralizing antibody responses gradually wane against several variants of concern (VOCs) after vaccination with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine messenger ...RNA-1273 (mRNA-1273). We evaluated the immune responses in nonhuman primates that received a primary vaccination series of mRNA-1273 and were boosted about 6 months later with either homologous mRNA-1273 or heterologous mRNA-1273.β, which encompasses the spike sequence of the B.1.351 Beta variant. After boost, animals had increased neutralizing antibody responses across all VOCs, which was sustained for at least 8 weeks after boost. Nine weeks after boost, animals were challenged with the SARS-CoV-2 Beta variant. Viral replication was low to undetectable in bronchoalveolar lavage and significantly reduced in nasal swabs in all boosted animals, suggesting that booster vaccinations may be required to sustain immunity and protection.
Adjuvanted soluble protein vaccines have been used extensively in humans for protection against various viral infections based on their robust induction of antibody responses. Here, soluble ...prefusion-stabilized spike protein trimers (preS dTM) from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were formulated with the adjuvant AS03 and administered twice to nonhuman primates (NHPs). Binding and functional neutralization assays and systems serology revealed that the vaccinated NHP developed AS03-dependent multifunctional humoral responses that targeted distinct domains of the spike protein and bound to a variety of Fc receptors mediating immune cell effector functions in vitro. The neutralizing 50% inhibitory concentration titers for pseudovirus and live SARS-CoV-2 were higher than titers for a panel of human convalescent serum samples. NHPs were challenged intranasally and intratracheally with a high dose (3 × 10
plaque forming units) of SARS-CoV-2 (USA-WA1/2020 isolate). Two days after challenge, vaccinated NHPs showed rapid control of viral replication in both the upper and lower airways. Vaccinated NHPs also had increased spike protein-specific immunoglobulin G (IgG) antibody responses in the lung as early as 2 days after challenge. Moreover, passive transfer of vaccine-induced IgG to hamsters mediated protection from subsequent SARS-CoV-2 challenge. These data show that antibodies induced by the AS03-adjuvanted preS dTM vaccine were sufficient to mediate protection against SARS-CoV-2 in NHPs and that rapid anamnestic antibody responses in the lung may be a key mechanism for protection.
Abstract only
The objective was to evaluate gut microbiome in relation to recent aspartame and Acesulfame‐K artificial sweetener consumption. Thirty‐one adults completed a four‐day food record and ...provided a fecal sample on the fifth day. Fecal samples were analyzed for bacterial DNA using Multitag Pyrosequencing. Median values for bacterial abundance across non‐consumers and consumers were compared. Overall bacterial abundance profiles across non‐consumers and consumers were compared using UniFrac analysis. Seven participants (23%) consumed aspartame. Seven participants (23%) consumed Acesulfame‐K. These were not the same seven individuals, and three individuals consumed both aspartame and Acesulfame‐K. No participants consumed saccharin. There were no differences in median bacterial abundance for any bacteria (class or order) across consumers and non‐consumers of either aspartame or Acesulfame‐K. The median Bacteriodetes:Firmcutes ratio also did not differ across aspartame non‐consumers (0.96, range: 0.15‐2.97) and consumers (1.08, range: 0.69‐1.87), (p‐value=0.60). Relative abundance of bacteria by class is illustrated for Acesulfame‐K non‐consumers vs. consumers. The median Bacteriodetes:Firmcutes ratio was non‐significantly higher in Acesulfame‐K non‐consumers (1.11, range: 0.14‐2.97) and consumers (0.79, range: 0.38‐2.97), (p‐value=0.74). These results suggest that recent intake of aspartame or Acesulfame‐K is not associated with overall gut microbiome profile in adults. Further studies with more individuals are warranted to evaluate lower abundance microbial taxa or interactions other factors. Support: Internal Funding
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