Figure 4. The antisera elicited by 4-KLH vaccine in the presence of adjuvant can recognize cancer cells expressing the native STn antigen.

1-KLH and 4-KLH were immunized five times at biweekly intervals and animals were challenged via the tail vein 7 days after the 4th immunization with 2 × 10⁵ CT-26 cells. The mice were bled by tail vein on day 13 after the third immunization and on day 14 after the fifth immunization. Serological IgG analysis results on B16 cells (A), LS-B cells (B), CT-26 cells (C) and LS-C cells (D) after the third and the fifth immunization with 1-KLH and 4–KLH by flow cytometry. (D) The competitive inhibition of serum recognition of LS-C cells using carbohydrate STn (compound 1) as inhibitor. The results are representative of at least two independent experiments.