TABLE 1.

Subclass ratio in serum before and 2 weeks after booster (day 21)^a

Immunization	Mean subclass ratio ± SEM at day:
	20	36
Antigen-conjugated microparticles orally	2.4 ± 1.6	0.9 ± 0.7
Free antigen orally	4.1 ± 1.9	1.0 ± 0.8
Microparticles + free antigen orally	6.8 ± 2.2	1.2 ± 0.4
Antigen-conjugated microparticles intra-muscularly	0.3 ± 0.3	0.3 ± 0.2
Free antigen intramuscularly	0.02 ± 0.1	0.3 ± 0.1

^aValues represent means ± standard errors of the means (SEM) of the ratio IgG1/(IgG2a + IgG2b) from six mice.