Enhanced splenic bacterial clearance and neutrophilia in anti-NK1.1-treated mice infected with Pseudomonas aeruginosa.
The purpose of the present study was to further delineate the role of natural killer (NK) cells in the early stages of resistance to infection by Pseudomonas aeruginosa, strain PAO1. Intravenous injection of the monoclonal antibody alpha-NK1.1 resulted in an 82% reduction in NK cell activity of normal mice, as measured by a standard 4-hour 51Cr release assay. Splenic bacterial clearance was examined in mice treated with this antibody 12 h prior to infection with a sublethal dose (10(6)) of PAO1. At 2, 4, and 6 h postinfection there was significant enhancement (up to 10-fold) of clearance in mice treated with alpha-NK1.1 when compared to untreated infected control animals. Interestingly, the enhanced clearance of PAO1 in the spleens of NK-depleted mice was found to be coupled to a significant increase in neutrophils. Normal murine spleens were found to contain 1-2% neutrophils, which increased to 6-7% following sublethal infection. However, in mice treated with alpha-NK1.1 and infected, splenic neutrophils increased up to 15% during the early stages of infection. The data presented here suggests that NK cells do not have direct bactericidal activity against Pseudomonas, but may regulate other effector cells, such as neutrophils-an indirect role for natural killer cells, probably mediated in vivo by their production and secretion of cytokines.
Newton
D W
DW
Department of Biology, University of Dayton, OH 45469-2320.
Runnels
H A
HA
Kearns
R J
RJ
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D015169:Colony Count, Microbial; D003602:Cytotoxicity, Immunologic / Q000276:immunology; D005260:Female; D007694:Killer Cells, Natural / Q000276:immunology*; D007958:Leukocyte Count; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D009504:Neutrophils / Q000276:immunology*; D011552:Pseudomonas Infections / Q000276:immunology*; D011550:Pseudomonas aeruginosa / Q000502:physiology*; D013154:Spleen / Q000276:immunology / Q000382:microbiology*
D000911:Antibodies, Monoclonal