Thermal injury elevates the inflammatory monocyte subpopulation in multiple compartments.
Recent publications have demonstrated that human resident and inflammatory monocyte (IM) subpopulations have equivalents in rodents. The effect of thermal injury upon these subpopulations has not been studied. Mice were given a scald burn and killed on postburn days (PBDs) 2, 4, and 8. Bone marrow, blood, and spleen white cells were isolated, and the percentage of resident monocytes (CD11b LY6C), IMs (CD11b LY6C), and monocyte progenitors (macrophage-colony-forming unit [M-CFU]) were determined. The ability of each monocyte population to make TNF-alpha was determined by intracellular cytokine staining. Finally, the ability of sorted fractions from PBD 8 spleen to inhibit lymphocyte proliferation was performed. We noted that there was an increase in M-CFU in the blood and spleen at PBD 8, but the marrow only had a nonsignificant increase in M-CFU. All compartments showed a significant increase in the number of IMs by PBD 8, but no significant changes in resident monocytes were seen. In all compartments, IMs were a major source of TNF-alpha. The postburn increase in IMs and monocyte progenitors in the spleen was accompanied by an increase in the monocyte chemokine monocyte chemoattractant protein 1 and constitutively high levels of the progenitor chemokine stromal-derived factor 1alpha. After burn injury, mice deficient in the receptor for soluble TNF-alpha had equal levels of splenic M-CFU and monocytes, as did wild-type mice, suggesting that this cytokine is not essential for this effect. We conclude that in this model, IMs are a significant source of in vivo TNF-alpha.
Noel
John G
JG
Shriners Hospital for Children, 3229 Burnet Avenue, Cincinnati, OH 45229, USA. gnoel@shrinenet.org
Osterburg
Andrew
A
Wang
Quan
Q
Guo
Xialing
X
Byrum
Denise
D
Schwemberger
Sandy
S
Goetzman
Holly
H
Caldwell
Charles C
CC
Ogle
Cora K
CK
D000818:Animals; D001854:Bone Marrow Cells / Q000276:immunology; D002056:Burns / Q000097:blood / Q000276:immunology / Q000473:pathology*; D049109:Cell Proliferation; D018932:Chemokine CCL2 / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000473:pathology*; D051379:Mice; D008954:Models, Biological; D009000:Monocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D023461:Myeloid Progenitor Cells / Q000166:cytology / Q000276:immunology; D010446:Peptide Fragments / Q000378:metabolism; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000276:immunology; D053319:Tumor Necrosis Factor Decoy Receptors / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D018932:Chemokine CCL2; D016207:Cytokines; D010446:Peptide Fragments; D047888:Receptors, Tumor Necrosis Factor, Type I; D053319:Tumor Necrosis Factor Decoy Receptors; D014409:Tumor Necrosis Factor-alpha; C508645:monocyte chemoattractant protein 1 (66-77); C069521:recombinant human tumor necrosis factor-binding protein-1