TABLE 4.

Stimulation of different IgG isotypes after i.n. immunization with PspA–IL-2 or PspA–GM-CSF^a

Immunogen	Anti-PspA titer
	IgG1	IgG2a	IgG3	IgA
PspA	<20	<20	<20	<200
PspA–IL-2	42,256	8,419	2,237	<200
PspA–GM-CSF	142,411	131	708	<200
PspA (alhydrogel)	23,705	78	1,203	<200

^aGroups of five DBA/2 mice were immunized i.n. with PspA–IL-2 (5 μg), PspA–GM-CSF (5 μg), or PspA (5 μg) on days 0, 7, and 14. Another group of mice were immunized s.c. with PspA (5 μg) in alhydrogel on day 0 and boosted with PspA (5 μg) on day 14. Mice were bled 14, 28, and 44 days later, and anti-PspA titers were determined by ELISA.