Protection against <i>Neisseria meningitidis</i> nasopharyngeal colonization relies on antibody opsonization and phagocytosis by neutrophils
Bibliographic record
Abstract
ABSTRACT Neisseria meningitidis is a human-restricted pathogen that can cause a rapidly progressing invasive meningococcal disease, yet it is also a regular inhabitant of the human nasopharynx. Vaccines that target N. meningitidis aim to prevent invasive disease, but their ability to interfere with nasal colonization could effectively eradicate this bacteria in a population, and so is an important target for meningococcal vaccine design. While protection against invasive meningococcal disease is classically attributed to IgG-dependent complement activation and bacterial killing, there remains no indication of what confers protection against nasopharyngeal colonization, making it impossible to deliberately target this stage during vaccine development. Moreover, without understanding what confers protection in this tissue site, it is impossible to understand the level of susceptibility within a population. To address this, we have taken advantage of the CEACAM1-humanized mouse model to characterize immune effectors that protect against nasal carriage of N. meningitidis . Protection against nasal colonization could be induced by live mucosal infection or by parenteral immunization with heat-killed bacteria. Mice possessing genetic deficiencies in B cells were used to evaluate the role of B cells and a specific antibody response, while neutrophil and complement depletion were used to evaluate their respective contributions to immunization-induced protection against meningococcal nasal carriage. Despite the essential role for complement killing in preventing invasive meningococcal disease, complement was not required for protection against nasal colonization. Instead, N. meningitidis- specific antibodies and neutrophils were both required to protect mice against the nasal infection. Combined, these data suggest that phagocytic bacterial killing is necessary for protection against mucosal colonization by N. meningitidis , indicating that nasal immunoglobulin with the ability to promote opsonophagocytosis must be considered as a correlate of protection against meningococcal carriage. AUTHOR’S SUMMARY Neisseria meningitidis can cause devastating and often fatal systemic infections including sepsis and meningitis, yet it frequently lives in the throat of healthy individuals. Vaccines developed against some meningococcal strains allow the individual to resist becoming colonized by the bacteria, an effect that protects them from disease and prevents them from spreading the bacteria to others, while other vaccines effectively protect against disease but still allow the individual to carry the bacteria in their throat. The reason for this difference has remained difficult to explain. Here, we use a ‘humanized’ mouse model that allows N. meningitidis infection in the nasal passages to establish that effective protection against nasal colonization requires that antibodies present within the infected mucosal tissues can coat the bacteria so that they are engulfed by neutrophils, a potent bacteria-killing white blood cell that is recruited to the site of infection. These findings suggest that antibodies with the ability to promote neutrophil recognition and killing of N. meningitidis should be the goal of future vaccines, and the presence of these can be used to consider an individual’s resistance against this terrible pathogen.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".