Fig. 5: Supplementation of L-alanine enhances anti-TB immunity.

CFU counts (A) and relative intracellular CFU ratio (B) in MPMs treated with 1 mM L-alanine, 50 nM rifampicin (RIF) or combination of 1 mM L-alanine and 50 nM RIF followed by H37Rv infection for 3 and 24 h (MOI = 2). CFU counts (C) and relative intracellular CFU ratio (D) in MPMs treated with 1 mM L-alanine or 50 nM rifampicin (RIF) followed by multidrug-resistant M. tuberculosis (MDR) infection for 3 and 24 h (MOI = 2). E Survival curve of 6-week-old female SCID mice treated with ddH₂O or 30 mg/ml L-alanine and aerosol infected with roughly 100 CFUs per mouse of H37Rv. CFU assay (F), histological score (G) and histopathological assay (H) with acid-fast staining and haematoxylin and eosin staining in lung tissues of C57BL/6J mice treated with ddH₂O or 30 mg/ml L-alanine after 28 days of H37Rv infection. Data in (A–D) are representative of one experiment with at least three independent biological replicates; (A–D) n  =  3, each circle represents one technical repeat (mean ± s.e.m); (F) n = 6 mice (mean ± s.e.m); (G) n   =  3 mice (mean ± s.e.m). Two-tailed unpaired Student’s t-test (A–D), Log-rank test (E) and two-sided Mann-Whitney U-test (F, G) were used for statistical analysis. P values are shown in (A–G). 1#, 2# and 3# in (H) represent lung tissues from 3 mice. Scale bars, 100 μm (top; original magnification, ×400) and 20 μm (bottom; original magnification, ×1,000). Source data are provided as a Source Data file.