IgM of mice infected with Mycobacterium bovis interacts selectively with T cells

In the course of experimental BCG infection in mice, cytotoxic autoantibodies (CAA) of IgM class reacting with thymocytes and T lymphocytes were found. CAA were not cytotoxic for bone marrow cells and B lymphocytes. CAA reacts with PNA+, glass wool-adherent, hydrocortisone-sensitive thymocytes. The reaction of thymocytes with CAA and complement, prevented suppressor cell induction from such treated cells. The importance of CAA in mycobacterial infection is discussed.