Restorative Effects of A Newly Synthesized Peptide, Obiopeptide-1, in Cyclophosphamide- or Carrageenan-pretreated Mice Infected with Opportunistic Bacteria

Large numbers of cyclophosphamide- or carrageenan-pretreated immunosuppressed adult ddY mice died within 10 days after inoculation with several species of opportunistic bacteria, including P. aeruginosa, K. pneumoniae, E. coli, S. aureus and methicillin resistant S. aureus. When immunosuppressed mice were administered bacteria in combination with two 100 μg/mouse intramuscular doses of a newly synthesized peptide, Obiopeptide-1 (OP-1), survival rates increased significantly. At 24 and 48 hours after intraperitoneal inoculation with P. aeruginosa, counts of viable organisms from the livers, spleens, lungs, hearts, and kidneys of mice that were administered cyclophosphamide in combination with OP-1 were significantly lower than counts from mice that were administered cyclophosphamide alone. Bacteriocidal activity of peritoneal cells, neutrophils and monocyte-macrophages was higher in OP-1 pretreated mice than in non-OP-1 treated mice. This newly synthesized peptide, OP-1, is a potential immunomodulator which increases host resistance against bacterial infection. The peptide may also function as a nonspecific blood stimulating factor