Peptide Schedule
Lactoferricin B (LfcinB)25 residues (approx.)FKCRRWQWRMKKLGAPSITCVRRAFEach bubble = one amino acid. Size = residue mass. Color = chemical class.Uses closest standard amino acids for non-standard residues.Lactoferricin B (LfcinB)
Benefits
About Lactoferricin B (LfcinB)
Lactoferricin B is a 25-residue antimicrobial peptide (FKCRRWQWRMKKLGAPSITCVRRAF) derived from the N-terminal region of bovine lactoferrin through pepsin hydrolysis. First isolated and characterized in 1992 by Bellamy et al., it represents one of the most studied naturally derived antimicrobial peptides. The peptide adopts a twisted beta-sheet conformation in solution, stabilized by an intramolecular disulfide bridge. Its high cationic charge and amphipathic structure enable direct interaction with negatively charged microbial membranes, causing membrane permeabilization and cell death. Beyond antimicrobial activity, LfcinB exerts immunomodulatory effects by promoting macrophage and NK cell activation, and demonstrates selective cytotoxicity against cancer cell lines while sparing normal cells. These multifunctional properties have made it a subject of intense research in antimicrobial defense, cancer biology, and immune modulation.
Who Should Consider Lactoferricin B (LfcinB)
- Researchers studying antimicrobial peptide mechanisms and resistance
- Scientists investigating anti-biofilm strategies against drug-resistant pathogens
- Oncology researchers exploring selective anticancer peptides
- Immunologists studying innate immune activation and NK cell biology
- Researchers developing topical antimicrobial formulations
- Food scientists investigating natural preservative peptides
How Lactoferricin B (LfcinB) Works
Lactoferricin B exerts its primary antimicrobial activity through electrostatic interaction between its cationic residues (Arg, Lys) and anionic components of microbial membranes (lipopolysaccharide in Gram-negative bacteria, lipoteichoic acid in Gram-positive bacteria). Upon membrane binding, the amphipathic structure inserts into the lipid bilayer, causing membrane depolarization, pore formation, and loss of cytoplasmic contents. This carpet-like or toroidal pore mechanism leads to rapid bactericidal activity. Against cancer cells, LfcinB preferentially targets the negatively charged phosphatidylserine exposed on tumor cell outer membranes, triggering apoptosis through mitochondrial membrane disruption, cytochrome c release, and caspase activation. Immunomodulatory effects occur via stimulation of macrophage toll-like receptor 4 (TLR4) signaling, promoting NF-kB-mediated cytokine production (IL-6, TNF-alpha) and enhanced phagocytic activity. LfcinB also activates NK cells through upregulation of granzyme B and perforin expression.
What to Expect
Rapid membrane interaction with target microorganisms. In vitro bactericidal activity observed within 15-60 minutes at effective concentrations.
With repeated dosing, sustained antimicrobial pressure on target pathogens. Early macrophage activation and increased phagocytic activity.
Measurable enhancement of innate immune markers. Elevated NK cell activity in animal models. Anti-biofilm effects begin to manifest.
Peak immunomodulatory effects in research models. Reduction in bacterial colonization in chronic infection models.
Continued antimicrobial and immunomodulatory support. Evaluate biomarkers for efficacy and safety. Consider transitioning to off-cycle.
Dosing Protocol
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 50mcg | Daily |
| Moderate | 100mcg | Daily |
| Aggressive | 200mcg | Daily |
Note: Lactoferricin B (LfcinB) is a 25-amino-acid cationic antimicrobial peptide (residues 17-41 of bovine lactoferrin) generated by pepsin cleavage. It contains an amphipathic beta-sheet stabilized by a single disulfide bond (Cys19-Cys36) and carries a net charge of approximately +8 at physiological pH. LfcinB demonstrates broader and more potent antimicrobial activity than its parent protein lactoferrin. It has been studied extensively for its direct membrane-disrupting mechanism against bacteria, fungi, and parasites, as well as its immunomodulatory and antitumor properties. Research use only — not approved for clinical use.
How to Inject Lactoferricin B (LfcinB)
Reconstitute lyophilized Lactoferricin B with bacteriostatic water. For subcutaneous injection, administer in the abdominal area or upper arm using an insulin syringe. For topical research applications, LfcinB can be formulated in a hydrogel or saline solution and applied directly to the target area. Due to its cationic nature, avoid mixing with anionic buffers or detergents that may neutralize charge-dependent activity. Store reconstituted solution refrigerated and use within 14 days.
Cycling Protocol
Limited clinical cycling data. Based on antimicrobial peptide research protocols, 8 weeks on with a 4-week off period is a reasonable framework. Monitor immune markers and inflammatory cytokines during use.
Pharmacokinetics
Source: Estimated half-life of 2-4 hours based on in vivo studies of cationic antimicrobial peptides of similar size and charge (PMID 22380935)
Loading the interactive decay curve.
Side Effects
Generally well-tolerated at research doses. Injection site irritation (redness, mild swelling) possible due to cationic charge. At high concentrations, potential for hemolytic activity against mammalian erythrocytes — toxicity is dose-dependent and typically observed only at supraphysiological levels. Mild gastrointestinal discomfort if used orally. Limited human safety data — most tolerability information derived from in vitro and animal models.
Contraindications
- Known hypersensitivity to lactoferrin or bovine milk-derived proteins
- Pregnancy and breastfeeding — no human safety data available
- Active autoimmune conditions — immunostimulatory effects may exacerbate autoimmune flares
- Severe hemolytic anemias — cationic peptides may have dose-dependent hemolytic potential
- Concurrent immunosuppressive therapy — LfcinB may counteract immunosuppression
- Individuals with cow milk protein allergy (potential cross-reactivity)
Drug Interactions
- Immunosuppressants (cyclosporine, tacrolimus, corticosteroids) — LfcinB promotes immune activation, potentially counteracting immunosuppressive effects
- Conventional antibiotics (synergistic effects reported with ampicillin, gentamicin) — may allow dose reduction of antibiotics
- Anticoagulants — lactoferrin-derived peptides may have mild anti-thrombotic properties; monitor clotting parameters
- Iron supplements — lactoferricin retains partial iron-binding capacity from parent lactoferrin
- Other cationic antimicrobial peptides — additive or synergistic membrane-disrupting effects
Storage & Stability
Molecular Profile
Related Peptides
References
- Lactoferricin B, a novel antimicrobial peptide derived from bovine lactoferrin (Biochem Biophys Res Commun 1992)PubMed 1540605
- Antitumor activity and mechanism of action of bovine lactoferricin (Int J Cancer 2004)PubMed 14991572
- Lactoferricin: a lactoferrin-derived peptide with antimicrobial, antiviral, antitumor and immunological properties (Biochem Cell Biol 2012)Review
- Mechanism of action of bovine lactoferricin on membranes (Biochimie 2009)PubMed 19063936
- Antibiofilm activity of lactoferrin-derived peptides against Pseudomonas aeruginosa (Biometals 2014)PubMed 24770988