CTLA4 and neoplasm: In 2015 Vétizou et al. found that a significant decrease in activated effector Cd4 + T cells and TILs are occurred in tumor-bearing mice treated with broad-spectrum antibiotics or housed in germ-free conditions, resulting in ineffective CTLA-4 blockade.23 Reduction of Bacteroidales and Burkholderiales in the faces of these microbiota-depleted mice was identified.