Elevated IgG responses in infants are associated with reduced prevalence of Mycobacterium tuberculosis infection

Research output: Contribution to journalArticlepeer-review

Authors

  • Erin Logan
  • Angelique Kany Kany Luabeya
  • Humphrey Mulenga
  • Dunja Mrdjen
  • Cynthia Ontong
  • Michele Tameris
  • Helen McShane
  • Thomas J Scriba
  • Mark Hatherill

External organisations

  • 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.

Abstract

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.

Details

Original languageEnglish
Article number1529
Number of pages10
JournalFrontiers in immunology
Volume9
Publication statusPublished - 2 Jul 2018

Keywords

  • Mycobacterium tuberculosis infection, Antibody, Enzyme-linked immunosorbent assay, Bacille Calmette-Guérin, Vaccine, Helminth