Treatment with the αGC-loaded CD1d-CD19 fusion limits tumor growth in vivo. (A) Freshly isolated hu-iNKT cells were plated with ⁵¹Cr-labeled MC38-CD19⁺ at varying E:T ratios with no stimulus (no Ag), PBS44, or ULFP or LFP (1 μg/mL). After 16 to 18 hours, culture supernatants were collected, radioactivity quantified, and percent specific lysis calculated. Depicted are results obtained using iNKT cells from 3 independent healthy donors. (B) Mice were grafted subcutaneously with 700 000 MC38-CD19⁺ cells, and treatment was started 72 hours later. Mice were treated every 3 days for a total of 6 doses CD1d-CD19 with either phosphate-buffered saline (control), αGC-loaded or unloaded CD1d-CD19 fusion (40 μg), or equivalent amounts of αGC-loaded or unloaded irrelevant Cd1d-Her2 fusion (40 μg). Mice were analyzed after 3 weeks. (C) Excised tumors from 1 representative experiment. ▲, no visible or palpable tumors. Weight (D) and volume (E) of excised tumors. Data in panels D-E are presented as mean ± SD of 4 to 5 mice per group from 1 of 2 independent experiments. Significance was determined by unpaired 2-tailed Student t test (D) or 2-way ANOVA (A,E). *P < .05, **P < .01.