Interleukin 2 (IL-2) is an interleukin, a T-cell growth factor (TCGF), and a type 1 cytokine that plays a key role in regulating T-cell responses. It’s also a 15.5 -16 kDa protein. Its discovery dates back to 1972 and was identified as the first fully-characterized human interleukin.  IL-2 is primarily produced by T helper (activated CD4+ cells) and monitors the activities of white blood cells, the cells responsible for immunity. Besides regulating white blood cells, IL-2 plays a crucial role as a natural response to microbial infections within the body and has the capabilities to discern between foreign and non-foreign objects in the human body. To mediate its actions, IL-2 must bind to IL-2 receptors, expressed by lymphocytes. If you’re looking for higher quality, human IL-2 recombinant, leverage discounted human il 2 protein from Shenandoah Biotech.

Functions of Interleukin-2

Some of its important functions include regulating the growth and differentiation of B lymphocytes and stimulating cell-mediated immune responses. It also intensifies the proliferation of cytotoxic cell clones. In vitro, IL-2 is a growth factor. However, it acts as a mediator of self-tolerance in vivo, which interests tumor immunotherapy investigators. In other areas like the cell cycle of neoplastic cells, the role of IL-2 is yet to be discovered.

Although the proliferation of other cells by IL-2 is stimulated or remains intact, a particular set of human tumor cells are inhibited from growing. What’s more, low levels of IL-2 are typically registered in severe clinical stages of human tumors. Because of this observation, most immunotherapies for a range of tumors use recombinant IL-2 as a possible treatment. However, certain tumors can generate their own IL-2, a strategy they employ to encourage tumor growth.

Functioning Capacity

As mentioned earlier, IL-2 plays crucial roles in our immunity, tolerance, and several primary functions of the immune system. That’s partly because it has a direct impact on T cells. For instance, IL-2 inhibits autoimmune diseases from developing during the maturation progress of T cells in the thymus. This is successful because IL-2 can encourage the differentiation of some immature T cells. After the differentiation, the resulting regulatory T cells suppress other T cells primed to attack normal body cells. In other differentiation processes, T cells transform into effector T cells and progress into memory T cells following stimulation from an antigen. This process helps combat body infections. Also, IL-2 encourages the cell killing of cytotoxic T cells and natural killer cells. 

Application of Interleukin 2 in Medicine

The Food and Drug Administration (FDA) approves Proleukin, a derivative of the recombinant interleukin-2—Aldesleukin, for cancer treatment. Recombinant DNA technology is employed in its manufacture. Also, several European countries approve Proleukin as a cancer treatment (renal cell cancer, malignant melanoma). The solution is used in large intermittent doses and extensively applied in consistent amounts.

However, IL-2 dosage varies in U.s and across the globe. Also, different states have colliding views on dosages’ efficacy (and side effects). For instance, a higher dosage for cancer treatment is used in the United States, predetermined by the cancer type, patients’ health status, and their response to the treatment. Typically, patients undergo a 5-day treatment, three daily sessions lasting 15 minutes, and the process runs continuously. They are afterward allowed ten days of recovery duration from treatment. An inpatient basis and intravenous delivery are employed to monitor side effects effectively.

Local Application

Anticancer therapy is more successful than Systemic therapy if IL-2 is locally applied to the tumor, as proved by early clinical studies. This happens over different dosages without having significant side effects.

 Tumor blood vessels are more easily damaged than proper functioning vessels upon the effects of IL-2. Once locally applied in tumor residing regions, blood flow inside tumor cells is disrupted, initiating the destruction of tumor tissues. Dosage estimation for local application of IL-2 is about 100-1000-fold lower. This makes the systemic dose of IL-2 insufficient to trigger side effects. However, most patients experience a painful injection as a significant side effect.

And as far as IL-2 toxicity, it lacks a wide therapeutic window. Therefore, the nature or severity of side effects encountered by patients is often linked to the dosage level. For the instance of its local application, IL-2 spans varying magnitudes of the therapeutic window. The typical side effects registered by most patients include low blood pressure, diarrhea, drowsiness (confusion), loss of appetite and nausea (vomiting).

Some reported side effects are more severe, such as seizures, breathing problems, serious infections, allergic reactions, kidney problems, heart problems, and more varying complications. Overall, vascular leak syndrome is the most popularized side effect as far as high-dose IL-2 therapy falls.

In conclusion, IL-2 is a cytokine employed in the treatment of cancer. It also has other therapeutic functions, as well as some side effects. Its effectiveness varies according to the dosage and mode of delivery. You should talk to your doctor if you have any questions or concerns about its use.

By Manali