Antimicrobial / Immune Research Peptides Guide
Overview
This guide covers 9 research peptides in the Antimicrobial / Immune category. Each compound is evaluated on its evidence base, mechanism, safety profile, and current clinical status.
LL-37 — Preclinical
Evidence: D | Status: Investigational / Limited clinical trial data (topical wound healing RCT exists)
LL-37 is the only human cathelicidin antimicrobial peptide, a 37-amino-acid cationic peptide (sequence: LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES) with broad-spectrum antimicrobial activity against Gram-positive and Gram-negative bacteria, fungi,...
Use cases: Immune Support, Antimicrobial
Beta-Defensins — Basic Science / Endogenous Reference
Evidence: D | Status: Endogenous peptides. No therapeutic product in clinical development. Studied as biomarkers and templates for antimicrobial drug design.
Beta-defensins are a family of small cationic antimicrobial peptides (36-45 amino acids, MW ~4-5 kDa) produced by epithelial cells throughout the body.
Use cases: Immune Support, Antimicrobial Research
Alpha-Defensins — Basic Science / Endogenous Reference
Evidence: D | Status: Endogenous peptides. No therapeutic product in clinical development. Studied as biomarkers (e.g., synovial fluid alpha-defensin test for periprosthetic joint infection).
Alpha-defensins are a family of small cationic antimicrobial peptides (29-35 amino acids, MW ~3.5-4.5 kDa) with three characteristic intramolecular disulfide bonds.
Use cases: Immune Support, Antimicrobial Research, Diagnostics
Lactoferricin — Preclinical Only
Evidence: D | Status: Preclinical research only. No clinical trials registered for lactoferricin as a standalone therapeutic.
Lactoferricin is a 25-amino-acid antimicrobial peptide (f17-41 of bovine lactoferrin; MW ~3126 g/mol for bovine form) generated by pepsin digestion of lactoferrin.
Use cases: Antimicrobial Research, Immune Support
Melittin — Preclinical / Traditional Use
Evidence: D | Status: Preclinical. Bee venom therapy (apitherapy) is used in traditional medicine. No approved pharmaceutical product based on isolated melittin.
Melittin is a 26-amino-acid cationic amphipathic peptide (sequence: GIGAVLKVLTTGLPALISWIKRKRQQ, MW ~2846 g/mol) that constitutes approximately 40-60% of dry honeybee (Apis mellifera) venom.
Use cases: Antimicrobial Research, Anticancer Research
Histatin-5 — Basic Science / Endogenous Reference
Evidence: D | Status: Endogenous peptide. No therapeutic product in development. Studied as a template for antifungal drug design.
Histatin-5 is a 24-amino-acid histidine-rich cationic peptide (sequence: DSHAKRHHGYKRKFHEKHHSHRGY, MW ~3036 g/mol) found in human saliva.
Use cases: Antimicrobial Research, Oral Health
Pexiganan — Phase III (Not Approved)
Evidence: C | Status: Phase III completed. Two NDA submissions to FDA (1999 and 2016) — both unsuccessful. Not approved in any jurisdiction.
Pexiganan (MSI-78) is a 22-amino-acid synthetic analog of magainin 2, an antimicrobial peptide originally isolated from the skin of the African clawed frog (Xenopus laevis).
Use cases: Antimicrobial Research, Wound Care
Omiganan — Phase III (Not Approved)
Evidence: C | Status: Phase III completed for catheter infections (not approved, 2003). Phase III for rosacea (CLS001 by Cutanea Life Sciences, results ~2018). No regulatory approval.
Omiganan (MBI 226) is a 12-amino-acid synthetic cationic antimicrobial peptide (sequence: ILRWPWWPWRRK-NH2, MW ~1779 g/mol) derived from indolicidin, a natural antimicrobial peptide from bovine neutrophils.
Use cases: Antimicrobial Research, Dermatology
Brilacidin — Phase II Clinical Trials
Evidence: C | Status: Phase II completed for ABSSSI (positive results). Phase II for oral mucositis. Investigated for COVID-19 (in vitro). No Phase III initiated.
Brilacidin (PMX-30063) is a synthetic small-molecule defensin-mimetic (MW ~564 g/mol) developed by Innovation Pharmaceuticals (formerly Cellceutix).
Use cases: Antimicrobial Research, Anti-Infective Development
