Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/11/1996
Publication Date: N/A
Technical Abstract: Ovine pulmonary surfactant is bactericidal due to small (721.6 - 823.8 Da), anionic peptides; H-GDDDDDD-OH, H-DDDDDDD-OH, and H-GADDDDD-OH. Peptides in 0.14 M NaCl with 10 uM ZnCl2 induce bacterial killing comparable to defensins and beta-defensins (minimal bactericidal concentration (MBC)50 range 0.01-0.06 mM) but not in 0.14 M NaCl with 10 mM sodium phosphate buffer, pH 7.2 with 0.5 mM CaCl2, 0.15 mM MgCl2 (MBC50 range 2.8-11.5 mM). To assess the relationship between peptide composition and anti-Pasteurella haemolytica efficacy, analogs of SAAP were synthesized and tested for antibiotic activity. Overall, bactericidal activity varied among peptides. MBC50 of peptide analogs for P. haemolytica serotype A1 strain 82-25 were as follows for H-GDDDDDD-OH (44.4 uM), H-ADDDDDD-OH (24.0 uM), H-GADDDDD-OH (24.6 uM), H-AADDDDD-OH (26.1 uM) H-DDDDK-OH (71.5 uM), and H-GDDDK-OH (141.9 uM). Small, anionic peptides, distinct from larger cationic defensins, form a new class of antimicrobial peptides and may be important in innate defense against infection.