Purification of Immunosuppressive Factor from Capnocytophaga Ochracea

1 Department of Microbiology, Nihon University, School of Dentistry at Matsudo, Chiba 271 * Department of Oral Science, National Institute of Infectious Disease, Shinjuku-ku, Tokyo 162, Japan 2 Corresponding author: Dr K. Ochiai. Received May 12, 1997 Accepted March 28, 1998 Capnocytophaga , one of the genera of oral bacteria, has been implicated in the pathogenesis of several diseases, including endocarditis, septicaemia and disorders of the oral cavity such as abscesses and periodontal disease. This study examined sonic extracts (SE) of Capnocytophaga strains for their ability to alter lymphocyte function. the SE of tested Capnocytophaga caused dose-dependent suppression of spleen cells in response to mitogen. This suppressive effect was heat-labile and sensitive to the proteolytic enzyme pronase E. the suppressive factor (SF) was purified from SE of C. ochrasea by a combination of ultrogel-AcA34, high-pressure liquid DEAE ion-exchange chromatography and hydroxyapatite columns, which revealed a single band of 14 kDa by SDS-PAGE. Rabbit anti-serum against the purified SF inhibited the immunosuppression induced by SE of C. ochracea with the recovery of lymphocyte proliferation.