Postvaccination Interleukin-7 Treatment Induces Anticancer Immune Response

Treatment of an animal model with the immune modulator interleukin-7 (IL-7) following vaccination with a viral-borne antigen was found to significantly improve laboratory animals' immune response to cancer and their ability to survive the disease.

Investigators from the University of Toronto (ON, Canada) administered IL-7 to animals following the inducement of an immune response to a viral-borne antigen. IL-7 is a hematopoietic growth factor secreted by the stromal cells of the red marrow and thymus. IL-7 stimulates the differentiation of multipotent hematopoietic stem cells into lymphoid progenitor cells and stimulates proliferation of all cells in the lymphoid lineage (B and T lymphocytes and NK cells). It is important for proliferation during certain stages of B-cell maturation, T and NK cell survival, development, and homeostasis.

Results of the study published in the April 26, 2009, online edition of the journal Nature Medicine revealed that IL-7 treatment following vaccine-induced immune stimulation improved antitumor responses and survival. The improved immune response was associated with increased IL-6 production, augmented T helper cell differentiation, and the modulation of the expression of two ubiquitin ligases.

While short-term IL-7 therapy without prior vaccine-induced immune stimulation potently enhanced certain immune responses, it was inefficient in promoting antitumor immune responses. "We are extremely excited because our research has revealed the unexpected ways IL-7 works to break down barriers that naturally block the immune response to tumors. This is important because current vaccine approaches for immune therapy induce a response in just 1% to 3% of patients," said contributing author Dr. Pamela Ohashi, professor of medical biophysics and immunology at the University of Toronto.

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