Figure 5
IgG1 responses to RD1 restricted M.tb-specific antigens are negatively correlated with mycobacterial net growth. Antigen-specific IgG2 (A) and IgG1 (B) responses in pre-treatment samples from active TB (n = 21), LTBI (n = 30) and healthy control individuals (n = 20) were determined by ELISA. Negative correlations between IgG1 responses to ESAT-6/CFP-10 and BCG (C) and M.tb H37Rv (D) net growth were seen. Antigens used were M.tb H37Rv-derived LAM, cell membrane fraction, culture filtrate and ESAT-6/CFP-10. Optical densities (ODs) are reported following subtraction of the background and plotted on a Log10 scale. Points represent the mean of duplicates and bars are the median values with the interquartile range. After normality testing a Kruskal-Wallis test with Dunn’s correction for multiple comparisons was performed for each antigen. *Represents a p-value of <0.05, **a p-value of <0.01, ***a p-value of <0.005 and ****a p-value of <0.0001. Spearman’s rho and associated p-values are shown. Red circles = active TB, grey squares = LTBI and blue triangles = healthy controls.
