Cell surface expression of lymphocyte antigens was performed by monoclonal antibody staining of freshly isolated MMCs and PBMCs, followed by flow cytometry using a BDLSRII instrument (Becton-Dickinson, Palo Alto, California, United States) with analysis using FlowJo software (TreeStar). Monoclonal antibodies used in this study included: anti-human CD3-Pacific Blue (PB) (clone UCHT1) (BD Pharmingen), anti-human CD4-Alexa700 (clone RPA T4) ((BD Pharmingen), anti-human CD8 APC-Cy7 (clone SK1) (BD Pharmingen), anti-human CD38-PE (clone HIT2) (BD Pharmingen), and anti-human Ki67-PE (clone B56) (BD Pharmingen), and the appropriate isotype controls. Flow cytometric analyses were performed as previously described [3 (link)].