Circulating B lymphocytes as biomarkers for latent tuberculosis infection status in Uganda (360G-Wellcome-092779_Z_10_Z)

In this study, we aim to investigate whether the proposed stages of latency and disease in tuberculosis infection (acquired immune, quiescent, active or diseased) are accompanied by continual intervention by the immune system as reflected in a changing profile of B-cell responses to mycobacterial antigens. We propose to measure this by looking at the ratio of antigen-specific plasmablasts (PBs) to memory B cells (MBCs). In addressing this question we may also demonstrate that B cells play a greater role in the control of tuberculosis than currently appreciated. We will use an in house B cell ELISPOT to detect mycobacterial antigen-specific PBs and MBCs, and later use it in validating a flow cytometry method to detect antigen specific PBs and MBCs. Our key goals are: 1. To develop an in-house B cell ELISPOT with five mycobacterial-specific proteins. 2. To investigate whether the ratio between PBs and MBCs is related to the probable infection status of an individual (acquired immune, quiescent, active or diseased) using the in-house ELISPOT. 3. To develop a flow cytometry based method to detect PBs and MBCs specific for Mtb and validate this method against the in-house ELISPOT.