Homogeneity of antibody responses in tuberculosis patients

The goals of the present study were twofold: (i) to compare the repertoires of antigens in culture filtrates of in vitro-grown Mycobacterium tuberculo sis that are recognized by antibodies from noncavitary and cavitary tubercu losis (TB) patients and (ii) to determine the extent of variation that exis ts between the antigen profiles recognized by individual TB patients. Lipoa rabinomannan-free culture filtrate proteins of M. tuberculosis were fractio nated by one-dimensional (I-D) and 2-D polyacrylamide gel electrophoresis, and the Western blots were probed with sera from non-human immunodeficiency virus (non-HIV)-infected cavitary and nancavitary TB patients and from HIV -infected, nancavitary TB patients. In contrast to earlier studies based on recombinant antigens of M. tuberculosis which suggested that antibody resp onses in TB patients were heterogeneous (K, Lyashchenko et al., 1998, Infec t. Immun, 66:3936-3940, 1998), our studies with native culture filtrate pro teins show that the antibody responses in TB patients show significant homo geneity in being directed against a well-defined subset of antigens, Thus, there is a well-defined subset of culture filtrate antigens that elicits an tibodies during noncavitary and cavitary disease. In addition, another set of antigens is recognized primarily by cavitary TB patients. The mapping wi th individual patient sera presented here suggests that serodiagnostic test s based on the subset of antigens recognized during both noncavitary and ca vitary TB will enhance the sensitivity of antibody detection in TB patients , especially in difficult-to-diagnose, smear-negative, nancavitary TB patie nts.