Figure 7. The antisera elicited by 4-KLH vaccine in the absence of adjuvant can recognize cancer cells expressing the native STn antigen.

1-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. The mice were bled by tail vein on day 13 after the third immunization and on day 7 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 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 two independent experiments.