Cell mediated immunity to Corynebacterium parvum and its role in tumor control.

The injection of C. parvum provokes a transient cell-mediated immune response to its own bacterial antigens. During this period a subcutaneous challenge dose results in the appearance of a characteristic delayed type hypersensitivity (DTH) skin reaction. If a suspension of syngeneic tumor cells is included in this challenge, they are destroyed in immune but not control animals. Similarly, solid tumors of limited size can be made to regress under these conditions. Adoptive transfer studies revealed that, in keeping with other DTH reactions, this effect was mediated by a population of rapidly dividing, theta-bearing lymphocytes. The ramifications of this response with respect to antitumor therapy are discussed.