CD3+CD8+CD137+ cells from SMM MP-CTL were evaluated for their peptide-specific IFN-γ production or CD107a degranulation in response to individual peptide pulsed K562-A*0201 cells.
A. Representative flow cytometric analyses of MP-CTL generated from one SMM patient demonstrated the peptide-specific IFN-γ production and CD107a degranulation (Q2 gated) by CD3+CD8+CD137+ cells in response to HLA-A2-specific heteroclitic XBP1 US184-192, heteroclitic XBP1 SP367-375, native CD138260-268, and native CS1239-247 peptide presented by K562-A*0201 cells. Baseline level of IFN-γ production and CD107a degranulation was established in response to no peptide pulsed or irrelevant HLA-A2-specific MAGE-3271-279 peptide pulsed K562-A*0201 cells.
B. The peptide-specific immune responses were demonstrated in MP-CTL generated from three different SMM patients. The MP-CTL from each individual SMM patient (patient #1, patient #2, patient #3) demonstrated a high level of dual immune activities, % IFN-γ+CD107a+ cells, within the gated CD3+CD8+CD137+ T cell population, in response to each relevant HLA-A2-specific XBP1 US, XBP1 SP, CD138 or CS1 peptide, presented by K562-A*0201 cells.