IgG antibody response to Mycobacterium tuberculosis curli pili (MTP) in people from different geographical regions in Sub-Saharan Africa

This study investigated whether people with active tuberculosis (TB) from different parts of Sub‑Saharan Africa produce detectable levels of a specific type of antibody (IgG) against a TB bacterial surface molecule called curli pili (MTP). The researchers tested hundreds of people with confirmed TB from three countries — The Gambia, South Africa, and Uganda — using a lab test that measures IgG antibodies against purified MTP. They found that people with active TB in The Gambia and South Africa tended to have higher levels of these anti‑MTP IgG antibodies compared with people without TB, showing that the immune system responds to this bacterial structure during illness. Anti‑MTP antibodies were present in both people with and without HIV. However, the strength of the antibody response and how well the test distinguished TB cases from non‑TB varied by region; in Uganda the antibody levels did not differ clearly between TB and non‑TB groups. Overall, the accuracy of the antibody test was relatively low and inconsistent across populations, suggesting it is not a reliable stand‑alone method for diagnosing TB in the high‑burden settings studied. The findings confirm that MTP triggers immune recognition during TB infection but also highlight that regional differences in immune responses may limit its use as a universal diagnostic marker outside of further refinement.