TABLE 2.

Titers of anti-TT IgG subclass antibodies in sera from intranasally immunized mice^a

Immunization	Antibody subclass	Antibody titersb
		Anti-TT	Anti-CT-B
TT only	IgG1	4,096	<64
	IgG2a	<64	<64
	IgG2b	<64	<64
	IgG3	<64	<64
TT + CT	IgG1	16,384	8,192
	IgG2a	256	4,096
	IgG2b	512	4,096
	IgG3	256	512

^aTiters of TT-specific antibodies in sera from mice intranasally immunized with TT only or TT in combination with CT (time point, day 21) were determined by ELISA using endpoint titration. 

^bSera from animals (n = 9) were pooled. The results are the mean titers of the groups.