Study of the function of
epitopes of
Mycobacterium tuberculosis antigens contributed significantly toward better understanding of the immunopathogenesis and to efforts for improving
infection and disease control. Characterization of genetically permissively presented
immunodominant epitopes has implications for the evolution of the host-parasite relationship, development of immunodiagnostic tests, and subunit prophylactic
vaccines. Knowledge of the determinants of cross-sensitization, relevant to other pathogenic or environmental mycobacteria and to host constituents has advanced.
Epitope-defined IFNγ assay kits became established for the specific detection of
infection with tubercle bacilli both in humans and cattle. The CD4
T-cell epitope repertoire was found to be more narrow in patients with active disease than in latently infected subjects. However, differential diagnosis of active TB could not be made reliably merely on the basis of
epitope recognition. The mechanisms by which HLA polymorphism can influence the development of multibacillary
tuberculosis (TB) need further analysis of
epitopes, recognized by Th2 helper cells for B-cell responses. Future
vaccine development would benefit from better definition of protective
epitopes and from improved construction and formulation of subunits with enhanced immunogenicity.
Epitope-defined serology, due to its operational advantages is suitable for active case finding in selected high disease incidence populations, aiming for an early detection of infectious cases and hence for reducing the transmission of
infection. The existing knowledge of HLA class I binding
epitopes could be the basis for the construction of
T-cell receptor-like
ligands for immunotherapeutic application. Continued analysis of the functions of mycobacterial
epitopes, recognized by T cells and
antibodies, remains a fertile avenue in TB research.