Serum IgM glycosylation associated with tuberculosis infection in mice

Changes in serum glycans discriminate between disease statuses in cancer. A similar connection has not been established in the context of infectious diseases such as tuberculosis (TB). The inflammation arising from infection by Mycobacterium tuberculosis may affect host protein glycosylation,thereby providing information about disease status in TB. A mouse model of infection was used to study glycoprotein N-glycosylation in serum. Following digestion of serum glycoproteins with peptide-N-glycosidase F (PNGase F), released glycans were permethylated and analyzed by multidimensional mass spectrometry (MS). Conditions included naive or Mycobacterium bovis BCG-vaccinated animals, which were either uninfected or infected with M. tuberculosis. MS results were validated by lectin blotting. We found that both glycoprotein fucosylation and sialylation were particularly sensitive to M. tuberculosis infection. We observed that M. tuberculosis infection elevates serum IgM levels and induces changes in glycosylation that could inform about the disease.