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. 2020 Mar 3;130(4):1808–1822. doi: 10.1172/JCI128459

Figure 5. Coincubation of sera with Mtb with an intact capsule or AM-coupled beads reduces anti-AM IgG titers and Ab-mediated phagocytosis in THP-1 and human monocyte-derived macrophages.

Figure 5

(A) Anti-AM IgG titers in heat-inactivated sera (1:100) before (Non) and after depletion of Abs against the Mtb surface (H37Rv, grown without detergent) or Mtb capsular AM (coupled to beads). Sera tested were from 2 TST+IGRA+ (L) and 2 TST+IGRA– (T) subjects with high anti-AM IgG titers. No significant difference in anti-AM IgG titer reduction was observed between the 2 depletion methods (P = 0.23, paired t test). (B) Comparison of Ab effects between nondepleted (Non) and anti–Mtb surface or anti-AM Ab–depleted sera (10%) on Mtb phagocytosis by THP-1 cells. (C) Reduction of Mtb phagocytosis by human monocyte-derived macrophages (MDMs) coincubated with sera (10%) depleted of Ab against the Mtb surface (H37Rv). Columns represent mean of duplicates (circles). Because of the limited availability of cells and the focus on comparing nondepleted with antigen-specific Ab–depleted sera, FBS was not tested in duplicates.