CD4 and diabetes mellitus: Fifty percent of the diabetic NOD mice injected with low dose (25 × 109 vg/mouse) AAV2/8-HLP-hINSco, and also treated with repeated injections of YTS177, achieved reversal of diabetes (here defined as blood glucose levels decreasing to below 13 mM), while none of the mice treated with isotype control antibody, vector alone or anti-CD4 antibody alone did (Fig. 5b).