A single administration of hIL-7-hyFc induces long-lasting T-cell expansion with maintained effector functions

• Published in: Blood advances 2022-12, Vol.6 (23), p.6093-6107
• Main Authors: Kim, Sojeong, Lee, Sang Won, Koh, June-Young, Choi, Donghoon, Heo, Minkyu, Chung, Jae-Yong, Lee, Byung Ha, Yang, Se Hwan, Sung, Young Chul, Lee, Howard, Shin, Eui-Cheol, Park, Su-Hyung
• Format: Article
• Language: English
• Subjects: Adult; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Proliferation; Humans; Interleukin-7 - pharmacology; Regular; T-Lymphocyte Subsets
• ISSN: 2473-9529; 2473-9537
• DOI: 10.1182/bloodadvances.2021006591

•A single hIL-7-hyFc administration induced a sustained increase in the numbers of T cells, but not regulatory T cells, in healthy adults.•The effector functions of antigen-specific CD8+ T cells were preserved after hIL-7-hyFc administration. [Display omitted] Interleukin-7 (IL-7) is an essential cytokine for T-cell homeostatic proliferation and maintenance. Clinical studies have shown the potential benefits of IL-7 therapy in various diseases associated with lymphopenia. However, the kinetics of the T-cell response to a single administration of IL-7 in humans have not been fully elucidated. Here, we investigated the effects of Fc-fused long-acting recombinant human IL-7 (hIL-7-hyFc, efineptakin alfa) on lymphocytes in healthy adults after a single subcutaneous or intramuscular administration. Administration of hIL-7-hyFc increased the CD8+ and CD4+ T-cell numbers up to 2.5-fold, with corresponding upregulation of Ki-67 and Bcl-2 expression, peaking at day 3 or 7. Regulatory T cells (Tregs) did not expand. Among CD8+ and CD4+ T cells, all T-cell subsets (TN, TEM, TCM, TEMRA, and TSCM) increased for 56 days. The T-cell receptor repertoire diversity of naive CD8+ and CD4+ T cells was increased by hIL-7-hyFc, whereas the memory T-cell subsets did not differ between day 56 and day 0. Transcriptomic analysis revealed that hIL-7-hyFc induced robust T-cell expansion without changes in gene expression profiles associated with T-cell functions or genes related to T-cell exhaustion, senescence, and anergy. The effector functions of antigen-specific CD8+ T cells were preserved after hIL-7-hyFc administration. Our results suggest that hIL-7-hyFc administration induced a sustained increase in the numbers of CD8+ and CD4+ T cells, but not Tregs, without qualitative changes. These results support the potential of hIL-7-hyFc as a treatment for patients with compromised T-cell immunity or as a vaccine adjuvant.