Fig. 5: Qualitatively distinct PPD-specific antibody responses in ‘resisters’ compared with LTBI individuals. | Nature Medicine

Fig. 5: Qualitatively distinct PPD-specific antibody responses in ‘resisters’ compared with LTBI individuals.

From: IFN-γ-independent immune markers of Mycobacterium tuberculosis exposure

Fig. 5

a, Graphs depict the AUCs calculated from the ratio of live to total intracellular bacterial burden in primary human monocyte-derived macrophages after treatment with purified IgG at 0.1 mg ml–1, 0.01 mg ml–1 and 0.001 mg ml–1 (left) from ‘resisters’ (n = 40) and TST/IGRA-positive LTBI controls (n = 39). Extension of analysis to additional donors was performed at a single concentration of purified IgG of 0.1 mg ml–1 due to sample availability (middle). Levels of secreted IL-1β from supernatants were measured by ELISA and are shown relative to no antibody treatment. Purified IgG from individuals in this study, with culture-confirmed pulmonary TB (ATB), is shown as a benchmark. Each line represents one healthy macrophage donor individual. For dot plots, lines are medians. The statistical significance was calculated using Wilcoxon’s matched-pairs signed rank, and two-tailed P values are shown. b, The calculated avidity against PPD from pooled plasma from ‘resisters’ (n = 40), TST/IGRA-positive LTBI controls (n = 39) and healthy, HIV-uninfected North Americans (n = 10) are shown, with lines representing the fitted curves and dotted lines the 95% confidence intervals. Each plasma group was tested in triplicate, with associated calculated avidity represented in the dot plot. The statistical significance was calculated using the Student’s t-test, and a two-tailed P value is indicated. OD, optical density or absorbance. ce, Plasma from ‘resisters’ (n = 40) and LTBI controls (n = 39) was assayed for the ability to mediate: PPD and ESAT6/CFP10-specific, antibody-dependent, monocyte-mediated cellular phagocytosis (c); PPD-specific, antibody-dependent neutrophil phagocytosis (d); and PPD-specific, NK cell activation by CD107a expression, macrophage inflammatory protein-1β and IFN-γ production (e). Data are representative of experiments performed in duplicate over three dilutions. Assays utilizing primary human neutrophils (d) and NK cells (e) were additionally performed utilizing three independent, healthy, HIV-negative donors. f, Affinity for FcγR2A(R), FcγR2A(H), FcγR3A(V) and FcγR3A(F) were determined using customized Luminex to PPD in ‘resisters’ (n = 40) and LTBI individuals (n = 39), using plasma diluted at 1:100. MFI is shown on the graph. The statistical significance was calculated using the Mann–Whitney U test, and P values are indicated. Dotted lines represent the median level detected in HIV-negative, healthy North American volunteers. g, Ratios of plasma levels of IgM, IgG and IgA1 reactive to PPD and LAM in ‘resisters’ (n = 40) and TST/IGRA-positive LTBI controls (n = 39) are depicted with medians and interquartile ranges. The statistical significance was calculated using the Mann–Whitney U test, and two-tailed P values are indicated. h, Ratios of plasma levels of IgG1, IgG2, IgG3 and IgG4 reactive to PPD in ‘resisters’ (n = 40) and TST/IGRA-positive LTBI individuals (n = 39) were measured by customized multiplex Luminex in serial dilutions. AUCs are depicted with medians and interquartile ranges. The statistical significance was calculated using the Mann–Whitney U test, and two-tailed P values are indicated. i, The relative distribution of glycoform substructures isolated from non-antigen-specific and PPD-specific IgG are depicted, with each column representing each individual. j, Principal component analysis demonstrates the overlapping profiles of ‘resisters’ (n = 40) and TST/IGRA-positive LTBI individuals (n = 39) in the dominant total glycans isolated from non-antigen-specific IgG compared with partially separating profiles from PPD-specific IgG. ADCP, antibody-dependent cellular phagocytosis; ADNP, antibody-dependent neutrophil phagocytosis; MIP, macrophage inflammatory protein.

Back to article page