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Study · Measured the body's own peptide · 2020

1 result

Seasonal Antimicrobial Activity of the Airway: Post-Hoc Analysis of a Randomized Placebo-Controlled Double-Blind Trial.

Vargas Buonfiglio LG, Vanegas Calderon OG, Cano M, Simmering JE, Polgreen PM, Zabner J, Gerke AK, Comellas AP

Nutrients27 Aug 2020Cited by 5 (Europe PMC)

PMID32867053 (opens in a new tab)PMCIDPMC7551279 (opens in a new tab)DOI10.3390/nu12092602 (opens in a new tab)PepBankPUB-32867053
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Summary

BackgroundIt is widely unknown why respiratory infections follow a seasonal pattern. Variations in ultraviolet B (UVB) light during seasons affects cutaneous synthesis of vitamin D3. Serum vitamin D concentration influences the expression of airway surface liquid (ASL) antimicrobial peptides such as LL-37.ObjectiveWe sought to determine the effect of seasons on serum vitamin D levels and ASL antimicrobial activity.MethodsForty participants, 18-60 years old, were randomized 1:1 to receive 90 days of 1000 IU vitamin D3 or placebo. We collected ASL via bronchoscopy and measured serum 25(OH) vitamin D from participants before and after intervention across seasons. We measured ASL antimicrobial activity by challenging samples with bioluminescent Staphylococcus aureus and measured relative light units (RLUs) after four minutes. We also investigated the role of LL-37 using a monoclonal neutralizing antibody.ResultsWe found that participants, prior to any intervention, during summer-fall (n = 20) compared to winter-spring (n = 20) had (1) decreased live bacteria after challenge (5542 ± 175.2 vs. 6585 ± 279 RLU, p = 0.003) and (2) higher serum vitamin D (88.25 ± 24.25 vs. 67.5 ± 45.25 nmol/L, p = 0.026). Supplementation with vitamin D3 increased vitamin D levels and restored ASL antimicrobial activity only during the winter-spring. The increased ASL antimicrobial activity seen during the summer-fall was abrogated by adding the LL-37 neutralizing antibody.ConclusionASL kills bacteria more effectively during the summer-fall compared to the winter-spring. Supplementation of vitamin D during winter-spring restores ASL antimicrobial activity by increasing the expression of antimicrobial peptides including LL-37.
CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study1

No result from this study comes from a test of the peptide.

Natural levels measured1

These results measure the body's own peptide. Nobody was given the peptide. They are not evidence about taking it. They are left out of key results, evidence counts and charts.

  1. 01LabEndogenous levelEx vivo tissueMechanism

    In airway surface liquid from participants in summer-fall, neutralizing the body's own LL‑37 with a monoclonal antibody abolished the increased antibacterial activity against S. aureus.

    In plain wordsIn lab tests of airway fluid, blocking the body's own LL‑37 removed the extra bacteria-killing activity seen in summer and fall.

    Peptide
    LL-37
    Outcome
    DecreaseAirway surface liquid antimicrobial activity after LL-37 neutralization
    Study

    humann: not reported in source

    airway surface liquid collected by bronchoscopy
    Outcome group
    Infection and antimicrobial activity · Respiratory

    Source sentences

    Summary
    The increased ASL antimicrobial activity seen during the summer-fall was abrogated by adding the LL-37 neutralizing antibody.
    3 context sentences
    Summary · context
    Forty participants, 18-60 years old, were randomized 1:1 to receive 90 days of 1000 IU vitamin D3 or placebo.
    Summary · context
    We measured ASL antimicrobial activity by challenging samples with bioluminescent Staphylococcus aureus and measured relative light units (RLUs) after four minutes.
    Summary · context
    We also investigated the role of LL-37 using a monoclonal neutralizing antibody.

    This result measures the body's own LL-37. Nobody was given the peptide. It is not evidence about taking it.

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

  1. Version 3Current

    9 Oct 2026, 18:17 UTC

    Study results updated

  2. Version 2

    9 Oct 2026, 03:03 UTC

    Study data updated · source update from Europe PMC

  3. Version 1

    9 Oct 2026, 02:57 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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