Figure 2.

Antibiotic treatment significantly reduces the immunotoxicity induced by anti-CD137

(A) Overview of the experimental design.

(B–E) Serum (B) ALT levels, (C) liver histological score, (D) representative H&E-stained liver cross-sections (areas of immune infiltration are indicated with arrows), and (E) IFNγ levels in serum assessed at 11 days after initiation of control (PBS) or anti-CD137 treatment (100 μg i.p., 3 doses 4 days apart) in ABX or no ABX mice.

(F and G) Frequency of (F) MC38 tumor rejection and (G) MC38 tumor growth in ABX and no ABX mice treated with PBS (control), anti-CD137 (100 μg i.p.), anti-PD1 (200 μg i.p), or anti-CD137 (100 μg i.p.) + anti-PD1 (200 μg i.p). Treatment was repeated 3 times 4 days apart and initiated when tumors were ∼40 to 50 mm² (day 10).

(H) Levels of ALT in serum collected 11 days after treatment initiation. n = 6–20 mice per group.

Statistical significance was determined by a Mann-Whitney test (B–F and H) or one-way ANOVA with Tukey’s post-test analysis (final tumor sizes in each group analyzed) (G). ∗p ≤ 0.05; ∗∗p ≤ 0.01; ∗∗∗∗p ≤ 0.0001. N.S., not significant. Data are represented as mean ± SEM. Results shown are pooled from 2 independent experiments (B–E) or from a single experiment (F–H).