Table 2. Immunological results after vaccination with synthetic carbohydrate conjugates in the absence of adjuvant.

	ELISA titer anti-STn		ELISA titer anti-modified-STn
	IgG	IgM	IgG
KLH	< 100	< 100	------
1-KLH	15309	< 100	15309
2-KLH	293812	< 100	588662
3-KLH	7384	< 100	14794
4-KLH	555186	< 100	1061530

KLH, 1-KLH, 2-KLH, 3-KLH and 4-KLH in the absence of adjuvant were immunized five times at biweekly intervals and animals were challenged via the tail vein 7 days after the 4th immunization with 1.5 × 10⁵ CT-26 cells. ELISA anti-STn or anti-modified-STn antibody titers after 5th immunization in the absence of adjuvant were determined by coating ELISA plates with the 1-BSA or modified-STn-BSA. Using the pooled antisera of all immunized mice obtained from 7 days after the fifth immunization, and the antibody titer was defined as the highest dilution showing an absorbance of 0.1, after subtracting background. Anti-STn IgM titers could not be detected when diluted 1:100 (expressed as < 100). The results are representative of three independent experiments.