CD28 and synovial sarcoma: In this study, we developed a humanized murine model that captures key immunopathological features of SS patients, and assessed its therapeutic utility.<h4>Methods</h4>PBMCs obtained from SS patients were stimulated with anti-CD3 and anti-CD28 antibodies for 15 hours, and 1 × 10<sup>6</sup> or 2 × 10<sup>6</sup> of these cells were intraperitoneally injected into NOD.Cg-<i>Prkdc</i> <sup>scid</sup> <i>Il2rg</i> <sup>tm1Wjl</sup>/SzJ (NSG) mice.