The tuberculin skin test, or the purified protein derivative (PPD) test, is based on:
a. delayed hypersensitivity cell-mediated immunity to certain antigenic components of the organism.
b. injection of M. tuberculosis under the skin and subsequent mild cutaneous infection.
c. antigen-antibody reactions occurring at the injection site.
d. humoral-mediated immune response.
A
The tuberculin skin test, or PPD (purified protein derivative) test, is based on the premise that following infection with M. tuberculosis, a patient will develop a delayed hypersensitivity cell-mediated immunity to certain antigenic components of the organism. To determine whether a person has been infected with M. tuberculosis, a culture extract of M. tuberculosis (i.e., PPD of tuberculin) is intra-cutaneous injected. After 48 to 72 hours a person who has been infected will exhibit a delayed hypersensitivity reaction to the PPD.
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