The intrinsic potency of naïve T cells from heparinized peripheral blood drives the response to CIK cell therapy.
T cells obtained from healthy donors and patients show variable proportions of T-cell subsets. Both CD4+ and CD8+ naïve cells (Tn) comprised a proportionately higher absolute number of healthy donor compared with patients (298 cells/μL vs. 156 cells/μL, p < 0.001, for CD4+Tn, and 157 cells/μL vs. 56 cells/μL, p < 0.001, for CD8+Tn). When there was only higher percentage of healthy donor compared with patients in CD8+ naïve cells (44.6% vs. 17.5%, p < 0.001) (Figure 3A and 3B). We next compared the proliferation of CIK cells from healthy donors and patients of absolute number of naïve CD4+ and naïve CD8+ cells in peripheral blood. We found that T cells from healthy donors exhibited a significantly greater proportion of naïve T cells compared to patients (Figure 3C and 3D). To understand whether CIK cells amplified from healthy donors with high naïve T cell counts had more activity and cytotoxicity. The proliferation of CIK cells that was associated with progressive differentiation during 15 days culture in vitro , and the number of T cells displaying an immune exhaustion phenotype such as CD3+PD-1+Tim-3+were significantly increased in samples from patients, but not in samples from healthy donors (Figure 3E ). However the percentage of proliferating CIK cells (CD3+CD56+Ki67+) from healthy donors was significantly greater than patients (Figure 3F). Moreover, cytotoxicity assays found that the in vitro cytolytic activity of CIK cells after amplification was higher in the samples from healthy donors than in samples from patients (Figure 3G). In our study, the frequency of naïve T cell in the patients with CR/PR were higher then in PD or SD. To determine if the higher proliferation rate and cytotoxicity of CIK cells amplified from patients with CR/PR could be maintained as long-term persistent immune activity, we checked the frequency and absolute numbers of naïve CD4+ and CD8+ cells in peripheral blood after 1 and 2 weeks transfer immunotherapy. Our results showed that PR/CR patients maintained the high level of CIK cells (CD3+CD56+) (Figure 3H and 2I) and IFN-γ -producing CIK cells (CD3+CD56+IFN-γ+) (Figure 3J and 3K) in peripheral blood. In summary, these findings indicated that patients with high absolute number of naïve CD4+ and naïve CD8+ cells could produce more CIK cells which likely play an important role in CIK immunotherapy.