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Open Access Research article

Immunogenicity of antigens from the TbD1 region present in M. africanum and missing from "modern" M. tuberculosis: a cross- sectional study

Bouke C de Jong12*, Abdulrahman Hammond13, Jacob K Otu1, Martin Antonio1, Richard A Adegbola1 and Martin O Ota12

Author Affiliations

1 Bacterial Diseases Programme, MRC Laboratories, POB 273, Banjul, the Gambia

2 New York University, 550 First Avenue, Smilow 901, New York, NY 10016, USA

3 FMPOS, University of Bamako, Point G, Bamako, Mali

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BMC Infectious Diseases 2010, 10:11  doi:10.1186/1471-2334-10-11

Published: 19 January 2010

Abstract

Background

Currently available tools cannot be used to distinguish between sub-species of the M. tuberculosis complex causing latent tuberculosis (TB) infection. M. africanum causes up to half of TB in West- Africa and its relatively lower progression to disease suggests the presence of a large reservoir of latent infection relative to M. tuberculosis.

Methods

We assessed the immunogenicity of the TbD1 region, present in M. africanum and absent from "modern" M. tuberculosis, in an ELISPOT assay using cells from confirmed M. africanum or M. tuberculosis infected TB patients without HIV infection in the Gambia.

Results

Antigens from the TbD1 region induced IFN╬│ responses in only 35% patients and did not discriminate between patients infected with M. africanum vs. M. tuberculosis, while PPD induced universally high responses.

Conclusions

Further studies will need to assess other antigens unique to M. africanum that may induce discriminatory immune responses.