Bacterial heat shock proteins directly induce cytokine mRNA and interleukin-1 secretion in macrophage cultures.
Bacterial heat shock proteins (hsp) have been shown to be important immunogens stimulating both T cells and B cells. However, little is known concerning the direct interactions between hsp and macrophages. In this study, we demonstrated that treatment of macrophage cultures with purified bacterial hsp, including Legionella pneumophila hsp60, Escherichia coli GroEL, Mycobacterium tuberculosis hsp70, Mycobacterium leprae hsp65, and Mycobacterium bovis BCG hsp65, increased the steady-state levels of cytokine mRNA for interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-6, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor as well as supernatant IL-1 secretion. This effect was shown not to be due to contamination of the hsp preparations with bacterial lipopolysaccharide. However, not all hsp induced cytokines; M. tuberculosis hsp10 showed minimal activity in our study. These results suggest that bacterial hsp might modulate immunity by rapidly and directly increasing cytokine production in macrophages.
Retzlaff
C
C
Department of Medical Microbiology and Immunology, University of South Florida College of Medicine, Tampa 33612.
Yamamoto
Y
Y
Hoffman
P S
PS
Friedman
H
H
Klein
T W
TW
D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology*; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D004926:Escherichia coli / Q000737:chemistry; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000235:genetics; D006360:Heat-Shock Proteins / Q000494:pharmacology*; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism; D007378:Interleukins / Q000235:genetics / Q000378:metabolism; D016952:Legionella pneumophila / Q000737:chemistry; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D009161:Mycobacterium / Q000737:chemistry; D012333:RNA, Messenger / Q000032:analysis; D013045:Species Specificity; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics
D001426:Bacterial Proteins; D016207:Cytokines; D006360:Heat-Shock Proteins; D007375:Interleukin-1; D007378:Interleukins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D016178:Granulocyte-Macrophage Colony-Stimulating Factor