Fig. 3.

Anti-Tn antibodies induced in cancer patients by the MAG-Tn3 vaccine recognize human Tn⁺ tumor cells. Patients were immunized on days 0, 21, 42, 63, 84, and 105 with the MAG-Tn3 vaccine formulated with the immunostimulant AS15. Patients 01, 02, and 03 received intramuscular injections of 30 µg MAG-Tn3, whereas patients 04, 05, 06, and 07 received 100 µg MAG-Tn3. Pre- and post-immunization sera were analyzed for their ability to recognize Jurkat (a) and MCF7 (b) Tn⁺ human cell lines. Cells were incubated with 1/50, 1/200, 1/800, or 1/3,200 diluted sera and then stained with anti-human IgM-FITC or IgG-PE antibodies and analyzed by flow cytometry. In a and b, the upper panels show histograms of one representative experiment, showing the mean fluorescence intensity (MFI) for IgM and IgG expression at a 1/50 serum dilution for each patient. The lower panels show the mean MFI ± SD obtained in two independent experiments with sera from patients immunized either with 30 or 100 µg of MAG-Tn3. The statistical significance of the differences was determined by the paired Student’s t test comparing the results obtained with sera before and after immunization. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001