Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 15, 1996
Publication Date: N/A
Technical Abstract: Pulmonary surfactant is bactericidal due to small, surfactant-associated anionic peptides (SAAP); H-GDDDDDD-OH, H-DDDDDDD-OH, and H-GADDDDDD-OH. The sequence of SAAP is similar to charge-neutralizing activation peptides found in some Group I serine protease, prohormone, and prodefensin zymogens. To assess bactericidal activity of these peptides, SAAP, trypsinogen activation peptide (TAP), and hormone PYL activation peptide from Xenopus laevis were synthesized and tested. Peptides induced killing of P. haemolytica and minimal bactericidal concentration50 was 0.11 plus or minus 0.01 SEM for TAP; 0.15 plus or minus 0.05 SEM for SAAP, and 0.05 plus or minus 0.01 for PYL. Antibacterial activity was also assessed in mice given Klebsiella pneumoniae via IT inoculation. After 18 h, mice given SAAP IT prior to infection or IV after infection had lower numbers of organisms in their lungs than mice given SAAP IT after infection. All mice had moderate suppurative pneumonia and moderate perivasculitis. SAAP, as part of pulmonary innate extracellular immune mechanisms, may suppress or reduce microbial colonization of the lower respiratory tract.