[Effects of Klebsiella pneumoniae on the expression of cytokines by polymorphonuclear neutrophil granulocytes in mice].
OBJECTIVE
To observe the effect of Klebsiella pneumoniae (Kle.p) on the expression of cytokines in mouse polymorphonuclear neutrophil granulocytes (PMNs).


METHODS
Mouse models of acute pneumonia were induced by intranasal inoculation of 30 microl PBS containing 1 x 10(7) Kle.p (heat-inactivated at 60 degrees C for 1.5 h). The mRNA and protein expressions of the cytokines in the isolated and purified PMNs were assayed by reverse transcriptional (RT)-PCR, Western blotting and enzyme- linked immunosorbent assay (ELISA), respectively.


RESULTS
Kle.p infection induced the mRNA expressions of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta in the early stage, and TNF-alpha mRNA reached its peak at 6 h and IL-1beta mRNA at 12 h after infection, both of which decreased 24 h after infection. Western blot analysis showed that the protein expressions of TNF-alpha and IL-1beta were the highest at 6 h, and decreased obviously at 24 h after infection. ELISA showed that the secretion of TNF-alpha peaked at 6 h and decreased obviously at 24 h after infection, while the peak of IL-1beta production occurred at 12 h and maintained the high level till 24 h after the infection.


CONCLUSIONS
TNF-alpha may participate in the immune defense of PMN against Kle.p infection mainly in the early stage of infection while IL-1beta mainly in the later stage.
Song
Hui
H
Department of Pharmacology, Medical College of Shantou University, Shantou 515041, China. drsonghui@yahoo.com.cn
Qian
Yuan-shu
YS
Dong
Hong-mei
HM
D000818:Animals; D005260:Female; D006098:Granulocytes / Q000378:metabolism*; D053583:Interleukin-1beta / Q000096:biosynthesis* / Q000235:genetics; D007710:Klebsiella Infections / Q000097:blood* / Q000378:metabolism; D007711:Klebsiella pneumoniae; D008297:Male; D051379:Mice; D011014:Pneumonia / Q000382:microbiology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics
D053583:Interleukin-1beta; D014409:Tumor Necrosis Factor-alpha