title: β-defensin-2 in breast milk displays a broad antimicrobial activity against pathogenic bacteria.
abstract: OBJECTIVE
  To describe the antimicrobial activity of β-defensin-2 produced in the mammary gland and secreted in human breast milk.
  
  
  METHODS
  The peptide production was performed by DNA cloning. β-defensin-2 levels were quantified in 61 colostrum samples and 39 mature milk samples from healthy donors, by an indirect enzyme-linked immunosorbent assay (ELISA). Using halo inhibition assay, this study assessed activity against seven clinical isolates from diarrheal feces of children between 0 and 2 years of age. The activity of β-defensin-2 against three opportunistic pathogens that can cause nosocomial infections was determined by microdilution test.
  
  
  RESULTS
  The peptide levels were higher in colostrum (n=61) than in mature milk samples (n=39), as follows: median and range, 8.52 (2.6-16.3) μg/ml versus 0.97 (0.22-3.78), p<0.0001; Mann-Whitney test. The recombinant peptide obtained showed high antimicrobial activity against a broad range of pathogenic bacteria. Its antibacterial activity was demonstrated in a disk containing between 1-4 μg, which produced inhibition zones ranging from 18 to 30 mm against three isolates of Salmonella spp. and four of E. coli. β-defensin-2 showed minimum inhibitory concentrations (MICs) of 0.25 μg/mL and 0.5 μg/mL for S. marcescen and P. aeruginosa, respectively, while a higher MIC (4 μg/mL) was obtained against an isolated of multidrug-resistant strain of A. baumannii.
  
  
  CONCLUSIONS
  To the authors' knowledge, this study is the first to report β-defensin-2 levels in Latin American women. The production and the activity of β-defensin-2 in breast milk prove its importance as a defense molecule for intestinal health in pediatric patients.
authors.affiliation: Laboratorio de Fisiología Molecular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela; Banco de Leche Humana, Hospital Universitario de Caracas, Caracas, Venezuela.
authors.forename: Joanna
authors.initials: J
authors.lastname: Baricelli
authors.affiliation: Laboratorio de Fisiología Molecular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela; Banco de Leche Humana, Hospital Universitario de Caracas, Caracas, Venezuela.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Rocafull
authors.affiliation: Laboratorio de Fisiología Molecular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela; Banco de Leche Humana, Hospital Universitario de Caracas, Caracas, Venezuela.
authors.forename: Desiree
authors.initials: D
authors.lastname: Vázquez
authors.affiliation: Banco de Leche Humana, Hospital Universitario de Caracas, Caracas, Venezuela; Laboratorio Delgado Launois, Clínica Lugo, Maracay, Venezuela.
authors.forename: Betsi
authors.initials: B
authors.lastname: Bastidas
authors.affiliation: Laboratorio de Fisiología Molecular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela; Banco de Leche Humana, Hospital Universitario de Caracas, Caracas, Venezuela.
authors.forename: Estalina
authors.initials: E
authors.lastname: Báez-Ramirez
authors.affiliation: Laboratorio de Fisiología Molecular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela; Banco de Leche Humana, Hospital Universitario de Caracas, Caracas, Venezuela. Electronic address: lthomas@ivic.gob.ve.
authors.forename: Luz E
authors.initials: LE
authors.lastname: Thomas
mesh_terms: D000328:Adult; D003126:Colostrum / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D004926:Escherichia coli / Q000187:drug effects; D005260:Female; D006801:Humans; D007774:Lactation / Q000276:immunology; D008826:Microbial Sensitivity Tests; D008895:Milk, Human / Q000737:chemistry*; D011247:Pregnancy; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012475:Salmonella / Q000187:drug effects; D055815:Young Adult; D023083:beta-Defensins / Q000032:analysis / Q000494:pharmacology*
chemical_list: C106641:DEFB4A protein, human; D023083:beta-Defensins
keywords: Agentes anti-infecciosos; Anti-infective agents; Antimicrobial cationic peptides; Breast milk; Defensinas; Defensins; Lactancy; Lactação; Leite materno; Peptídeos catiônicos antimicrobianos; hBD2