I have an problem in cloning of T cells specific to Porphyromonas gingivalis. Although we are using irradiated autologous LCL(40Gy), LCL starts to proliferate after 3-4 weeks. I would be appreciate if anybody could tell me how to cope with it. Thanks, Kazuhisa Yamazaki, Department of Periodontology, Niigata University School of Dentistry