Active CD4+ helper T cells directly stimulate CD8+ cytotoxic T lymphocyte responses in wild-type and MHC II gene knockout C57BL/6 mice and transgenic RIP-mOVA mice expressing islet β-cell ovalbumin antigen leading to diabetes. - Ye, Zhenmin; Ahmed, Khawaja Ashfaque; Hao, Siguo; Zhang, Xueshu; Xie, Yufeng; Munegowda, Manju Ankathatti; Meng, Qinghe; Chibbar, Rajni; Xiang, Jim (Autoimmunity, 2008)