[BCG cell wall proteins enhance clearance of Pseudomonas aeruginosa in rat lungs].
OBJECTIVE
To test the function of BCG cell wall proteins in enhancing the clearance of Pseudomonas aeruginosa in rat lungs.


METHODS
The BCG cells were broken by supersonic technique. The cell wall proteins were isolated by discontinues sucrose density-gradient centrifugation, and fractionated by Sephadex G-150 chromatography. The relative molecular mass of the isolated proteins was analyzed by SDS-PAGE. The hBD-1 gene mRNA expression in the SPC-A-1 cells was identified by Northern blot and RT-PCR. The cell wall component was injected intraperitoneally to the rats. Forty eight hours later, 5 X 10(6) CFU of P. aeruginosa ATCC27853 or Staphylococcus aureus ATCC25923 were inoculated via trachea. The bacteria colony in the supernatant of the homogenated lungs of the rats was counted 24 hours after the inoculation.


RESULTS
Two protein components of BCG cell wall were fractionated. The relative molecular mass of component 2 was in the range of 18 X 10(3) -30 X 10(3). The hBD-1 mRNA expression detected by Northern blot was markedly enhanced by the stimulation of heat-inactivated BCG whole cells. The BCG-induced hBD-1 mRNA expression in the SPC-A-1 cells detected by RT-PCR was mainly contributed by fraction 2 of the BCG cell wall proteins. The bacteria decreased significantly in the lungs of the rats with the injection of BCG component 2 (n=8, P<0. 01).


CONCLUSIONS
The fraction (relative molecular mass is 18 X 10(3) -30 X 10(3)) of BCG cell wall proteins improve the defense of rat lungs against P. aeruginosa infection.
Liu
Xiao-kang
XK
Department of Infection and Immunity, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
Zhou
Hui
H
Huang
Ning
N
Zhu
Bing-dong
BD
Feng
Yun
Y
Wu
Qi
Q
Wang
Bo-yao
BY
D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D002473:Cell Wall / Q000737:chemistry*; D023082:Defensins / Q000235:genetics; D005786:Gene Expression Regulation / Q000276:immunology; D008168:Lung / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology*; D008297:Male; D008970:Molecular Weight; D009163:Mycobacterium bovis / Q000166:cytology*; D011550:Pseudomonas aeruginosa / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
D001426:Bacterial Proteins; C478968:Defb1 protein, rat; D023082:Defensins; D012333:RNA, Messenger