Tuberculin Test: One of several skin tests to determine past or present tuberculosis infection. A purified protein derivative of the tubercle bacilli, called tuberculin, is introduced into the skin by scratch, puncture, or interdermal injection.Tuberculin: A protein extracted from boiled culture of tubercle bacilli (MYCOBACTERIUM TUBERCULOSIS). It is used in the tuberculin skin test (TUBERCULIN TEST) for the diagnosis of tuberculosis infection in asymptomatic persons.Tuberculosis, Bovine: An infection of cattle caused by MYCOBACTERIUM BOVIS. It is transmissible to man and other animals.HistoryBCG Vaccine: An active immunizing agent and a viable avirulent attenuated strain of Mycobacterium tuberculosis, var. bovis, which confers immunity to mycobacterial infections. It is used also in immunotherapy of neoplasms due to its stimulation of antibodies and non-specific immunity.Tuberculosis: Any of the infectious diseases of man and other animals caused by species of MYCOBACTERIUM.Tuberculosis, Pulmonary: MYCOBACTERIUM infections of the lung.Mycobacterium bovis: The bovine variety of the tubercle bacillus. It is called also Mycobacterium tuberculosis var. bovis.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Latent Tuberculosis: The dormant form of TUBERCULOSIS where the person shows no obvious symptoms and no sign of the causative agent (Mycobacterium tuberculosis) in the SPUTUM despite being positive for tuberculosis infection skin test.Hypersensitivity, Delayed: An increased reactivity to specific antigens mediated not by antibodies but by cells.Interferon-gamma Release Tests: The assay of INTERFERON-GAMMA released from lymphocytes after their exposure to a specific test antigen, to check for IMMUNOLOGIC MEMORY resulting from a previous exposure to the antigen. The amount of interferon-gamma released is usually assayed by an ENZYME-LINKED IMMUNOSORBENT ASSAY.Mycobacterium tuberculosis: A species of gram-positive, aerobic bacteria that produces TUBERCULOSIS in humans, other primates, CATTLE; DOGS; and some other animals which have contact with humans. Growth tends to be in serpentine, cordlike masses in which the bacilli show a parallel orientation.Skin Tests: Epicutaneous or intradermal application of a sensitizer for demonstration of either delayed or immediate hypersensitivity. Used in diagnosis of hypersensitivity or as a test for cellular immunity.