Recombinant integrin CD11b A-domain blocks polymorphonuclear cells recruitment and protects against skeletal muscle inflammatory injury in the rat.
The beta2 integrin CD11b/CD18 (CR3) is a major adhesion receptor of neutrophils, normally utilized to fend off infections. This receptor contributes, however, to multiple forms of non-infectious inflammatory injury when dysregulated as shown in gene knock-outs and through the use of blocking monoclonal antibodies. The major ligand recognition site of CR3 has been mapped to the A-domain in the CD11b subunit (CD11bA). The recombinant form of this domain exhibits a ligand binding profile similar to that of the holoreceptor. To assess the potential anti-inflammatory activity of CD11bA as a competitive antagonist of CR3 in vivo, we assessed its effects on a developed animal model of traumatic skeletal muscle injury in the rat. Recombinant soluble rat CD11bA-domain fused to glutathione-S-transferase (GST) was administered intravenously in a single dose at 1 mg/kg to nine groups of Wistar rats, five in each group, 30 min before inducing traumatic skeletal muscle injury. Control animals received either a function-blocking anti-CD11b/CD18 monoclonal antibody (1 mg/kg), non-functional mutant forms of the CD11bA (D140GS/AGA, T209/A, D242/A), recombinant GST or buffer alone. In control animals, the wounded muscle showed oedema, erythrocyte extravasation and myonecrosis both within and outside the immediate wounded area (5-10 mm zone) and influx of neutrophils was detected 30 min post-wound, followed by a second wave 3 hr later. Wild-type CD11bA- or anti-CD11b monoclonal antibody (mAb)-treated rats showed a comparable and significant decrease in the number of infiltrating PMN (78 + 4%, n = 70 and 86 +/- 2%, n = 50, respectively) and preservation of the muscular fibres outside the immediate zone of necrosis (75 + 4%, n = 70, 84 +/- 1%, n = 50, respectively), compared to controls. These data demonstrate that CD11bA can be an effective tissue-preserving agent in acute inflammatory muscular injury.
Zerria
K
K
Molecular Biotechnology Group, Institute Pasteur, Tunis, Tunisia.
Jerbi
E
E
Hammami
S
S
Maaroufi
A
A
Boubaker
S
S
Xiong
J P
JP
Arnaout
M A
MA
Fathallah
D M
DM
D000595:Amino Acid Sequence; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000276:immunology / Q000627:therapeutic use*; D000911:Antibodies, Monoclonal / Q000276:immunology; D039481:CD11b Antigen / Q000276:immunology / Q000627:therapeutic use*; D004195:Disease Models, Animal; D005260:Female; D008969:Molecular Sequence Data; D018485:Muscle Fibers, Skeletal / Q000276:immunology / Q000473:pathology; D018482:Muscle, Skeletal / Q000276:immunology* / Q000293:injuries / Q000473:pathology; D009220:Myositis / Q000276:immunology / Q000517:prevention & control*; D020556:Neutrophil Infiltration / Q000276:immunology*; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000627:therapeutic use; D016415:Sequence Alignment
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000911:Antibodies, Monoclonal; D039481:CD11b Antigen; D011994:Recombinant Proteins