Human interleukin-7 (IL7) is a multifunctional cytokine with a wide range of immune effects. For a long time, the understanding of IL-7 has been focused on influencing the growth, survival, and differentiation of B and T cells. However, in recent years, some studies have shown that IL-7 has a direct or indirect effect on anti-tumor effects. Let's take a look at the discovery, functions, and applications of IL-7 together.

The IL-7 signaling pathway promotes cell proliferation and apoptosis by regulating gene expression in the nucleus and inhibits cell level, including a decrease in promoting factors (such as Bad and Bax) and cell cycle factors (p21 CIP1 and p27 KIP1), as well as an increase in antioxidants (such as Bcl-XL, Bcl-2, McL-1) and glucose metabolism regulatory factors (Glut1, HXK II).

In tumors, IL-7 exhibits both promoting and anti-tumor effects. IL-7 rexerts anti-tumor effects by regulating immune releasing cytokines such as IFN-γ、IL-1β、 IL-1α and TNF-α. IL-7 can regulate the expression levels of Bcl-2 and Bcl-xL genes by binding with IL-7R to activate JAK/STAT5, PI3K/AKT, and Ras/ERK signals, thereby promoting tumor cell swelling and ischemia.

In addition, IL-7 and IL-7R are considered crucial for regulating the immune system in cancer patients. IL-7 may weaken the side effects of immunotherapy using IL-2. IL-7R mediated signal amplifiers are widely used to evaluate hematomas and some solid tumor models.

In addition to playing a role in immunity and tumors, IL-7 can also improve the humoral immune response induced by vaccines. As an adjuvant, IL-7 has been shown to enhance the response of CD4+T cells, CD8+T cells, and B cells to enhance vaccine efficacy, and to increase the production of memory T and B cells to prolong vaccine protection.

In summary, IL-7 has amplification applications, such as producing a new generation of CAR-T cells, prolonging the interval time of CAR-T cells and improving proliferation and killing ability through co expression of IL-7, producing superior vaccines, and enhancing anti-tumor effects.

Reference：

[1]. Two types of mouse T helper cell. IV. Th2 clones secrete a factor that inhibits cytokine production by Th1 clones..

[2]. Wang, C.; Kong, L.; Kim, S.; Lee, S.; Oh, S.; Jo, S.; Jang, I.; Kim, T.-D. The Role of IL-7 and IL-7R in Cancer Pathophysiology and Immunotherapy. Int. J. Mol. Sci. 2022, 23, 10412.