Elevated IgG responses in infants are associated with reduced prevalence of Mycobacterium tuberculosis infection
Research output: Contribution to journal › Article › peer-review
- Institute of Infectious Disease and Molecular Medicine/Division of Immunology, University of Cape Town, Cape Town, South Africa.
- South African Tuberculosis Vaccine Initiative (SATVI), Department of Pathology, Institute of Infectious Disease, Molecular Medicine and University of Cape Town, Cape Town, South Africa.
- The Jenner Institute, University of Oxford, Oxford, United Kingdom.
- Laboratory of Molecular and Experimental Immunology and Neurogenetics, UMR 7355, CNRS-University of Orleans and Le Studium Institute for Advanced Studies, Orléans, France.
Background: It is unclear whether antibodies can prevent Mycobacterium tuberculosis (Mtb) infection. In this study, we examined the relationship between total plasma IgG levels, IgG elicited by childhood vaccines and soil-transmitted helminths, and Mtb infection prevalence, defined by positive QuantiFERON (QFT) test.
Methods: We studied 100 Mtb uninfected infants, aged 4-6 months. Ten infants (10%) converted to positive QFT test (QFT+) within 2 years of follow-up for Mtb infection. Antibody responses in plasma samples acquired at baseline and tuberculosis investigation were analyzed by enzyme-linked immunosorbent assay and ImmunoCAP® assay.
Results: QFT- infants displayed a significant increase in total IgG titers when re-tested, compared to IgG titers at baseline, which was not observed in QFT+ infants. Bacille Calmette-Guérin (BCG) vaccine-specific IgG2 and live-attenuated measles vaccine-specific IgG were raised in QFT- infants, and infants who acquired an Mtb infection did not appear to launch a BCG-specific IgG2 response. IgG titers against the endemic helminth Ascaris lumbricoides increased from baseline to QFT re-testing in all infants.
Conclusion: These data show raised IgG associates with a QFT-status. Importantly, this effect was also associated with a trend showing raised IgG titers to BCG and measles vaccine. Our data suggest a possible protective association between raised antibody titers and acquisition of Mtb infection, potentially mediated by exposure to antigens both related and unrelated to Mtb.
|Number of pages||10|
|Journal||Frontiers in immunology|
|Publication status||Published - 2 Jul 2018|
- Mycobacterium tuberculosis infection, Antibody, Enzyme-linked immunosorbent assay, Bacille Calmette-Guérin, Vaccine, Helminth