Figure 1 from Dietary Fiber Lacks a Consistent Effect on Immune Checkpoint Blockade Efficacy Across Diverse Murine Tumor Models

<p>Microbiome composition is primarily shaped by diet type and is partially restored to chow-like levels by isolated fiber. <b>A,</b> Macronutrient and fiber composition of diets used in this study represented by %gram. In each tumor experiment, we used one of the low cellulose (LC)–purified diets (low fiber) and up to four of the high cellulose (HC)–purified diets (high fiber). LC = 2.5 to 2.6 %gram and HC = 14.9 to 15.7 %gram. Numbers in diet names represent %gram of inulin (In) in the diets. <b>B,</b> Schematic of the study design for the metagenomics (this figure) and metabolomics (<a href="#fig2" target="_blank">Fig. 2</a>). <b>C,</b> Principal coordinate analysis of all metagenomic samples from the B16-OVA experiment. PC, principal component. <b>D,</b> Shannon α diversity index across the dietary groups. Boxes represent the IQR with median shown as a horizontal line, whiskers extend from minimum to maximum values, and different letters above the bars indicate statistically significant differences between groups (<i>P</i> < 0.05) by a one-way ANOVA followed by the Tukey <i>post hoc</i> test. <b>E,</b> Relative abundances of microbiome composition at the phylum level, shown as the mean for each group. <b>F,</b> Heatmap depicting the relative abundances of 314 taxa after filtering out low-abundance taxa (<30 counts in >85% of samples). <b>G,</b> Venn diagram of significantly changed taxa in mice fed with chow vs. low–fiber-purified diet (LC_In0) and in mice fed with high–fiber (HC_In8)- vs. low–fiber (LC_In0)-purified diet (all B16-OVA tumors and anti–PD-1 treatment). <b>H,</b> Scatter plot of the 81 taxa altered by both chow and high-fiber–purified diet, displaying correlations between these two conditions. Each dot represents a specific taxon, with dot color indicating the taxon’s phylum as specified in the legend. For <b>C</b>–<b>H</b>, data are from <i>n</i> = 5 to 7 mice per group. FC, fold change. (<b>B,</b> Created with <a href="http://sciencefigures.org" target="_blank">sciencefigures.org</a>.)</p>