Figure 4.

Vα14Jα18⁺ (type I) NKT cells are not necessary for down-regulation of tumor immunosurveillance. (A) The wild-type (open diamonds), CD1d KO (closed triangles), and Jα18 KO (closed circles) BALB/c mice were injected subcutaneously with 10⁶ 15-12RM tumor cells on day 0, and tumor size was monitored over time. P < 0.05 by log-rank test between CD1d KO and wild-type or Jα18 KO mice. The results are representative of two experiments (n = 5). (B) The wild-type, CD1d KO, and Jα18 KO BALB/c mice were inoculated subcutaneously with 10⁴ CT26-L5 cells and subsequently monitored for survival (n = 5). Data are representative of two experiments. (C) The wild-type, CD1d KO, and Jα18 KO BALB/c mice were injected i.v. with 5 × 10⁵ CT26 cells. After 14 d, pulmonary metastases were enumerated. In one group, mice were treated with PC61 as in Fig. 1 C. CD1d KO mice had significantly fewer metastases (P < 0.002 by one-way ANOVA). The results are pooled from two independent experiments. The horizontal lines indicate the means. The data in Fig. 4 C and in Fig. 1 C were all obtained within the same larger experiments.