RT Journal Article SR Electronic(1) A1 Osada, Yasuaki A1 Ohtani, Tsuyoshi A1 Une, Tsutomu A1 Ogawa, Hidemasa A1 Nomoto, KikuoYR 1982 T1 Enhancement of Non-specific Resistance to Pseudomonas Pneumonia by a Synthetic Derivative of Muramoyl Dipeptide in Immunosuppressed Guinea Pigs JF Microbiology, VO 128 IS 10 SP 2361 OP 2370 DO https://doi.org/10.1099/00221287-128-10-2361 PB Microbiology Society, SN 1465-2080, AB A synthetic derivative of muramoyl dipeptide, 6-O-stearoyl-N-acetylmuramoyl-l-alanyl-d-iso-glutamine [L18-MDP(A)], showed a protective effect against bacteraemic and non-bacteraemic pneumonia caused by Pseudomonas aeruginosa in immunosuppressed guinea pigs. In about half of the animals treated with the compound before infection, death from bacteraemic pneumonia produced by intratracheal inoculation of P. aeruginosa was delayed for 7 d, although all of the animals infected without prior treatment with the compound died within 4 d of infection. Multiplication of the organisms in the lung was also suppressed for at least 10 d by treatment with the compound when the animals inhaled an aerosol of P. aeruginosa. In contrast, in untreated animals the numbers of bacteria in the lung gradually increased from 106 to 109 c.f.u. g−1, and a few animals in which the organism increased to 109 c.f.u. g−1 had died by 6 and 10 d after infection. In both healthy and immunosuppressed animals, the accumulation of polymorphonuclear leukocytes (PMNs) in a subcutaneous air-pouch injected with heat-killed organisms was augmented by subcutaneous treatment with L18-MDP(A) 1 d before bacterial injection. The phagocytic activity of peritoneal PMNs was also increased by treatment with this compound. The augmentation of protective mechanisms against pseudomonas pneumonia by L18-MDP(A) may be attributed at least partly to the increased chemotactic and phagocytic activity of PMNs., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-128-10-2361