ICOSLG and Granuloma: The granuloma area of ICOSL-KO mice was 4.64 ± 0.26, 2.89 ± 0.7 and 2.33 ± 0.73 × 104 μm2, which was significantly smaller than the infected C57BL/6 mice at 7, 9, and 12 wpi simultaneously (P < 0.001) (Fig. 1b, c).