Table 3.

Antibody concentrations against infecting serotype in 20 patients infected with Streptococcus pneumoniae

Serotype of infecting strain	Positive immune responsea (n = 11)			Negative immune responsea (n = 9)
	Concn (μg/ml)		Fold increase	Concn (μg/ml)		Fold increase
	Early sampleb	Late samplec		Early sample	Late sample
1	0.54	3.82	7.12	0.37	0.57	1.54d
				0.14	0.31	2.18d
				0.32	0.30	0.95d
				2.30	4.34	1.88d
				0.02	1.09	43.94d
3	0.06	1.38	24.08d
	0.10	1.71	16.45
4	0.01	1.47	100.95d	0.10	0.14	1.41d
8	0.26	0.74	2.86d	0.09	0.10	1.21
	1.22	12.24	10.04
9V	0.20	1.42	7.16	0.10	0.13	1.28d
				0.09	0.22	2.53d
14	0.02	1.67	110.89d
	0.05	1.15	22.84d
	0.05	3.35	66.74
19F	0.11	6.03	54.76d

^aResponse was defined as at least a 2-fold increase in antibody concentrations with an end concentration above 0.35 μg/ml. The fold increase against a single pneumococcal serotype had to be at least two times greater than the fold increase against any other serotype. All positive antibody responses were against the infecting serotype.

^bThe early serum sample was drawn at day 1 (days 0 to 3) of hospital admission.

^cThe late serum sample was drawn at day 30 (days 11 to 100) of hospital admission.

^dStrain was isolated from blood.