Table 5.

Avidity of anti-PPS antibodies from young and elderly.

Pre-immune serum GMC (95% CI)
		CPS	CPS + 22F	P value
PPS4	Young	0.19 (0.07–0.32)	0.21 (0.04–0.38)	0.091
	Elderly	0.22 (0.13–0.31)	0.22 (0.12–0.31)	0.646
PPS14	Young	0.28 (0.21–0.36)	0.27 (0.19–0.35)	0.711
	Elderly	0.43 (0.27–0.59)	0.42 (0.27–0.56)	0.196
Post-immune serum GMC (95% CI)
		CPS	CPS+22F	P value
PPS4	Young	0.35 (0.22–0.49)	0.40 (0.25–0.55)	0.053
	Elderly	0.43 (0.23–0.63)	0.46 (0.26–0.65)	0.014
PPS14	Young	0.47 (0.33–0.62)	0.41 (0.29–0.54)	0.618
	Elderly	0.68 (0.50–0.85)	0.66 (0.48–0.84)	0.715

Geometric Mean Concentration (GMC, M NaSCN) representing serum avidity by two different ELISA methods. CPS – serum adsorbed with CPS prior to ELISA. CPS+22F – serum absorbed with PPS22F and CPS prior to ELISA. P values shown in bold indicate a significant difference between absorption methods calculated using paired Student's T-test.