CD47 associates with alpha 5 integrin and regulates responses of human articular chondrocytes to mechanical stimulation in an in vitromodel

Table 1 Effect of anti-CD47/IAP, anti-TSP-1, and anti-SIRPα on mechanically induced changes in human articular chondrocyte membrane potential

		Membrane potential (-mV) (mean ± SEM)
Sample	Reagent	Resting	Reagent alone	Reagent + 0.33 Hz	Percentage change
Normal chondrocytes	Nil	25.0 ± 0.4	-	30.2 ± 0.6	+21^a
	Bric 126	26.2 ± 0.8	27.2 ± 0.4	27.6 ± 1.2	+2^b
	B6H12	25.8 ± 2.2	26.3 ± 1.9	17.1 ± 1.0	-35^a
Osteoarthritic chondrocytes	Nil	30.0 ± 1.9	-	17.4 ± 1.3	-42^a
	Bric 126	28.0 ± 1.6	28.0 ± 2.1	27.4 ± 1.8	-2^b
	Anti-TSP-1	29.6 ± 1.2	29.0 ± 0.8	29.8 ± 1.6	+3^b
	SE5A5	29.2 ± 1.0	29.0 ± 1.1	23.2 ± 0.8	-20^a

Membrane potentials of chondrocytes were measured at rest in the absence or presence of the appropriate antibody and after 20 minutes of mechanical stimulation at 0.33 Hz. Bric 126 is a function-blocking anti-CD47/IAP antibody. B6H12 is an anti-CD47/IAP antibody that has partial agonist activity. SE5A5 is an anti-SIRPα antibody. N = 5. ^ap < 0.001; ^bnot significant. IAP, integrin-associated protein; SEM, standard error of the mean; SIRPα, signal-regulatory protein-alpha; TSP-1, thrombospondin-1.

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