Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 1996
Publication Date: N/A
Technical Abstract: SAAP is a small (823.8 Da) peptide isolated from ovine pulmonary surfactant that is bactericidal in vitro for Gram-positive and Gram-negative bacteria. Antibacterial activity in vivo was assessed in CF1 mice as described by Kelly, et al., Surgery. 114, 140 (1993). Anesthetized mice were given 50 ul K. pneumoniae ATCC 10031 (5.8 x 106 CFU) via intratracheal (i.t.) inoculation at the laryngotracheal opening followed by treatment every 2 hrs (for 4 doses) with 100 ul i.v. inoculation of SAAP (4 mg/kg) in 0.14 M NaCl with 10 uM ZnCl2 (zinc saline solution) or by treatment every 2 hrs (for 4 doses) with 50 ul i.t. inoculation of SAAP (4 mg/kg) in zinc saline solution. SAAP (4 mg/kg) was also given once 20 min before K. pneumoniae i.t. inoculation. Control mice were given identical inoculations of organisms or SAAP. At 18 hrs post- infection, mice given SAAP i.t. prior to infection or i.v. after infection had the lowest numbers of organisms in their lungs. Mice given SAAP i.t. after infection had the highest number of organisms. All mice had similar lesions characterized by moderate suppurative pneumonia and moderate hyperviscosities. SAAP, as part of pulmonary innate extracellular immune mechanisms, may serve to suppress or reduce microbial colonization of the lower respiratory tract.