Antiviral Activity of Chicken Cathelicidin B1 Against Influenza A Virus.
Peng. Lianci L; Du. Wenjuan W; Balhuizen. Melanie D MD; Haagsman. Henk P HP; de Haan. Cornelis A M CAM; Veldhuizen. Edwin J A EJA
Key Findings
- Chicken cathelicidin CATH‑B1 reduced infection by up to 80% for three flu strains, while LL‑37 showed little effect.
- The antiviral action required the peptide to bind directly to the virus, leading to large aggregates that prevent entry.
- CATH‑B1 did not damage the virus shape or neuraminidase activity, but likely interferes with hemagglutinin binding.
Practical Outcomes
- For DIY health enthusiasts, the study suggests that simply taking LL‑37 supplements is unlikely to protect against flu. The effective mechanism—direct viral binding and aggregation—requires a peptide that isn’t currently available for human use. Until a safe, human‑compatible version is developed, this research offers limited actionable guidance.
Summary
Scientists tested several cathelicidin peptides, including the human peptide LL‑37, against flu viruses in a dish. They found that a chicken peptide called CATH‑B1 could cut infection rates by up to 80%, but LL‑37 barely worked. The chicken peptide works by sticking to the virus and clumping it together, which blocks the virus from entering cells.
Abstract
Cathelicidins (CATHs) are host defense peptides (HDPs) that play an important role in the innate immune response against infections. Although multiple functions of cathelicidins have been described, including direct antimicrobial activity and several immunomodulatory effects on the host, relatively little is known about their antiviral activity. Therefore, <i>in vitro</i> antiviral activity of chicken cathelicidins and the underlying mechanism was investigated in this study against different influenza A virus (IAV) strains. Our results show that chicken CATH-B1 has broad anti-IAV activity compared to other cathelicidins (CATH-1, -2, -3, LL-37, PMAP-23, and K9CATH) with an inhibition of viral infection up to 80% against three tested IAV strains (H1N1, H3N1, and H5N1). In agreement herewith, CATH-B1 affected virus-induced inflammatory cytokines expression (IFN-β, IL-1β, IL-6, and IL-8). Incubation of cells with CATH-B1 prior to or after their inoculation with virus did not reduce viral infection indicating that direct interaction of virus with the peptide was required for CATH-B1's antiviral activity. Experiments using combined size exclusion and affinity-based separation of virus and peptide also indicated that CATH-B1 bound to viral particles. In addition, using electron microscopy, no morphological change of the virus itself was seen upon incubation with CATH-B1 but large aggregates of CATH-B1 and viral particles were observed, indicating that aggregation might be the mechanism of action reducing IAV infectivity. Neuraminidase (NA) activity assays using monovalent or multivalent substrates, indicated that CATH-B1 did not affect NA activity <i>per se</i>, but negatively affected the ability of virus particles to interact with multivalent receptors, presumably by interfering with hemagglutinin activity. In conclusion, our results show CATH-B1 has good antiviral activity against IAV by binding to the viral particle and thereby blocking viral entry.
Study Information
pubmed
2020
2020-03-19T00:00:00.000Z
10.3389/fmicb.2020.00426
25
42