TABLE 1.

Serum antibody responses in mice 3 days after secondary intranasal immunization with TT plus CT

Pooled seruma	Antigenb	Antigen-specific serum antibody titersc
		IgM	IgG	IgA
Expt 1	TT	512	8,192	<128
	CT-B	<128	256	<128
Expt 2	TT	256	8,192	<128
	CT-B	<128	128	<128

^aSerum from mice (n = 5) was pooled. 

^bAntigen used in coating ELISA plates. 

^cAntigen-specific antibody titers were determined by ELISA using endpoint titration.