Table 1 Characteristics of human host defense peptides.

Human cathelicidin (cationic, α-helical structure)

hCAP18/LL-37

Escherichia coli; Pseudomonas aeruginosa; Staphylococcus aureus; Enterococcus faecalis; group A, B, and C Streptococcus; Klebsiella pneumoniae; Listeria monocytogenes; Salmonella typhimurium; Proteus vulgars; Proteus mirabilis; Burkholderia cepacia; Actinobacillus actinomycetemcomitans; Capnocytophaga spp; Candida albicans; HIV-1

Broad antimicrobial activity, antiviral and antifungal activity, endotoxin-binding properties, modulation of pro-inflammatory response, chemotactic, influence of cell proliferation and differentiation, promotion of wound healing and angiogenesis, induction of gene expression, induction of adaptive immunity

Neutrophils, keratinocytes, epithelial cells of the skin and testis, gastrointestinal and respiratory tract, mast cells, monocytes/macrophages, CD4⁺ cells, myelocytes, wound and blister fluid, airway fluid, seminal fluid, cervix, vagina, esophagus, mouth, tongue

Human β-defensins (cationic, disulfide bridges, β-sheet structure)

hBD-1

Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae. Staphylococcus aureus

Broad antimicrobial activity; antiviral and antifungal activity; chemotactic; induction of chemokines and cytokines; recruitment of immune cells; induction of adaptive immunity and pro-inflammatory cytokines such as IL-8, -18, and -20; degranulation of mast cells; promotion of phagocytosis; induction of dendritic cell maturation by TLR-4; LPS and LTS binding properties; inhibition of TNF-α production; induction of matrix-metalloproteinase (MMP); inhibition of MMP-inhibitors (TIMP-1/-2)

CD4⁺ and CD8⁺ T cells; dendritic cells; epithelial cells of skin, respiratory, gastrointestinal, and urogenital tract; trachea; uterus; pancreas; kidney; lung; prostate; placenta; thymus; testis; vagina; gingival intestine; conjunctiva; cornea; lachrymal and buccal mucosa; tongue; salivary gland; mammary glands; limb joints; astrocytes; microglia

hBD-2

Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae. Staphylococcus aureus. Streptococcus pneumoniae, Enterococcus faecalis, Candida albicans, Candida parapsilosis, Candida crusei, HIV-1

mast cells, CD4⁺ and CD8⁺ T cells; dendritic cells; skin; oral, pulmonal, and gastric epithelia; conjunctiva; cornea; astrocytes

hBD-3

Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae. Staphylococcus aureus. Staphylococcus carnosus. Streptococcus pyogenes. Streptococcus pneumoniae, Enterococcus faecalis, Burkholderia cepacia, Saccharomyces cerevisiae, Candida albicans, Candida parapsilosis, Candida crusei, HIV-1

Monocytes; CD4⁺ T cells; oral, respiratory, gastrointestinal, urinary, and skin epithelial cells; uterus; placenta; testis; esophagus; heart; neutrophils; trachea; skeletal muscle; tongue; kidney; liver; gastrointestinal tract; pharynx; tonsils; salivary glands