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ARS Home » Research » Publications at this Location » Publication #98378
Title: ANIONIC ANTIMICROBIAL PEPTIDE-LYSOZYME INTERACTIONS IN INNATE PULMONARY IMMUNITY

Author
item KALFA, V - VISITING SCI,NADC,AMES,IA
item BROGDEN, KIM

Submitted to: American Society of Microbiologists Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/30/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The respiratory tract contains numerous antimicrobial factors necessary for normal innate pulmonary defense including anionic peptides (AP) beta- defensins, alpha-defensins, antimicrobial fragments of surfactant proteins, lysozyme, secretory leukoprotease inhibitor, lactoferrin, human salivary mucin glycoprotein MG2, human salivary histatin 5, and cathelicidins. Despite differences in concentration, molecular mass, mechanism of action, and ionic charge, many of these molecules are thought to reside in airway surface liquid (ASL) simultaneously. However, little information exists concerning antimicrobial peptide antagonistic, additive, or synergistic interactions. Since both cationic lysozyme and AP are found in high concentrations in ASL, the purpose of this study was to assess their interaction in an isobologram configuration. For this, Pasteurella haemolytica, Micrococcus lysodeikticus, or Pseudomonas aeruginosa (10**3 CFU/ml) were added to egg white lysozyme (from 1000 to 0.98 ug /ml) and H- D-OH (from 2.0 to 0.03 mM) mixtures in 50, 100, or 150 mM NaCl; incubated for 2 hours; and then plated. With P. haemolytica, AP had antibacterial activity that decreased as the salt concentration increased. With P.haemolytica, lysozyme did not have antibacterial activity in any salt concentration. When combined, there was a slight antagonistic interaction in high lysozyme concentrations. With M. lysodeikticus, a slight synergistic interaction between lysozyme and AP was seen and with P. aeruginosa, no interactions were seen. In conclusion, egg white lysozyme and AP appear not to significantly interact but act independently of each other in ASL. Whether these same interactions occur with neutrophil lysozyme are not known and will have to be determined.