Antibody responses to mycobacterial antigens in patients immunized with BCG for the treatment of neoplastic disease.

Precipitin and agglutination antibody response to antigens of Mycobacterium tuberculosis was measured in 43 patients with neoplastic disease who were treated with weekly BCG or intratumor BCG vaccination. Resuspended freeze-dried Tice vaccine was shown to contain soluble mycobacterial antigens. Fourteen patients receiving weekly BCG vaccination developed intense precipitin and agglutination antibody response over the course of several months. Twenty-nine patients receiving intratumor and oral vaccination developed less intense antibody response. Twenty-one of 28 purified protein derivative (PPD)-negative patients converted their PPD. No correlation between antibody, PPD response and antitumor effect could be identified. The importance of identifying the soluble antigen in BCG and of defining the humoral response to purified antigens is discussed.