Monoclonal antibodies from humans with Mycobacterium tuberculosis exposure or latent infection recognize distinct arabinomannan epitopes

The surface polysacharide arabinomannan (AM) and related glycolipid lipoarabinomannan (LAM) play critical roles in tuberculosis pathogenesis. Human antibody responses to AM/LAM are heterogenous and knowledge of reactivity to specific glycan epitopes at the monoclonal level is limited, especially in individuals who can control M. tuberculosis infection. We generated human IgG mAbs to AM/LAM from B cells of two asymptomatic individuals exposed to or latently infected with M. tuberculosis. Here, we show that two of these mAbs have high affinity to AM/LAM, are non-competing, and recognize different glycan epitopes distinct from other anti-AM/LAM mAbs reported. Both mAbs recognize virulent M. tuberculosis and nontuberculous mycobacteria with marked differences, can be used for the detection of urinary LAM, and can detect M. tuberculosis and LAM in infected lungs. These mAbs enhance our understanding of the spectrum of antibodies to AM/LAM epitopes in humans and are valuable for tuberculosis diagnostic and research applications.
Elise Ishida et al. generate human monoclonal antibodies that can selectively recognize specific oligosaccharide epitopes of the polysaccharides arabinomannan and lipoarabinomannan, which are critical for M. tuberculosis pathogenesis. The authors demonstrate the utility of these antibodies in both diagnostic and laboratory settings, making them important tools for M. tuberculosis research.