Mycobacterial Heparin-Binding Haemagglutinin Adhesion-Induced Interferon & Antibody for Detection of Tuberculosis (Report‪)‬

Tuberculosis (TB) remains a major problem for most parts of the world, with nearly two million people being killed annually (1). A better definition of the humoral and cellular immune responses to Mycobacterium tuberculosis antigens such as heparin-binding haemagglutinin adhesin (HBHA) may have an important impact on the differential diagnosis and vaccine development. The mycobacterium HBHA is a surface-associated protein (2). Native HBHA (nHBHA) is modified at the C-terminal domain with a 20-26 methyl group after translation (3), while the recombinant HBHA (rHBHA) produced by Escherichia coli has no methyl groups (4). In pathogenic mycobacteria, HBHA is an adhesin for nonphagocytic cells (2,3,5) and is implicated in extra-pulmonary (EPTB) dissemination of M. tuberculosis from the lung, following initial host infection (3,6). HBHA can induce high levels of anti-HBHA antibodies in most patients with active TB, but not in healthy subjects with latent infection, BCG-immunized subjects and healthy controls (7). HBHA can also induce T-lymphocytes to produce large amounts of HBHA specific interferon gamma (IFN-[gamma]) from healthy human individuals as compared to those with active TB (4,8). Tests based on in vitro release of IFN-y by memory T lymphocytes have been introduced for the diagnosis of M. tuberculosis infection using M. tuberculosis-specific antigens, such as 6 kilodaltons ESAT-6 and culture filtrate protein CFP-10 of 10 kilodaltons (9,10). More recently, the HBHA-induced IFN-[gamma] release assay (IGRA) has been shown a great potential for the diagnosis of latent TB infection (7,11). Recent progress in protein purification systems has paved the path of purifying nHBHA from whole crude bacterium proteins (12).