TY - JOUR

T1 - Interleukin 21 therapy increases the density of tumor infiltrating CD8+ T cells and inhibits the growth of syngeneic tumors

AU - Søndergaard, Henrik

AU - Frederiksen, Klaus S

AU - Thygesen, Peter

AU - Galsgaard, Elisabeth D

AU - Skak, Kresten

AU - Kristjansen, Paul E G

AU - Odum, Niels

AU - Kragh, Michael

N1 - Keywords: Animals; Antineoplastic Agents; CD8-Positive T-Lymphocytes; Carcinoma, Renal Cell; Cell Line, Tumor; Female; Infusions, Parenteral; Injections, Subcutaneous; Interleukins; Kidney Neoplasms; Lymphocyte Activation; Lymphocytes, Tumor-Infiltrating; Melanoma, Experimental; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; T-Lymphocyte Subsets

PY - 2007

Y1 - 2007

N2 - Interleukin (IL)-21 is a recently discovered cytokine in early clinical development, which has shown anti-tumor activity in various animal models. In the present study, we examine the anti-tumor activity of IL-21 protein therapy in two syngeneic tumor models and its effect on the density of tumor infiltrating T cells. We treated mice bearing established subcutaneous B16 melanomas or RenCa renal cell carcinomas with intraperitoneal (i.p.) or subcutaneous (s.c.) IL-21 protein therapy and subsequently scored the densities of tumor infiltrating CD4(+) and CD8(+) T cells by immunohistochemistry. Whereas both routes of IL-21 administration significantly inhibited growth of small, established RenCa and B16 tumors, only s.c. therapy significantly inhibited the growth of large, established tumors. We found a greater bioavailability and significant drainage of IL-21 to regional lymph nodes following s.c. administration, which could account for the apparent increase in anti-tumor activity. Specific depletion of CD8(+) T cells with monoclonal antibodies completely abrogated the anti-tumor activity, whereas NK1.1(+) cell depletion did not affect tumor growth. In accordance, both routes of IL-21 administration significantly increased the density of tumor infiltrating CD8(+) T cells in both B16 and RenCa tumors; and in the RenCa model s.c. administration of IL-21 led to a significantly higher density of tumor infiltrating CD8(+) T cells compared to i.p. administration. The densities of CD4(+) T cells were unchanged following IL-21 treatments. Taken together, these data demonstrate that IL-21 protein has anti-tumor activity in established syngeneic tumors, and we show that IL-21 therapy markedly increases the density of tumor infiltrating CD8(+) T cells.

AB - Interleukin (IL)-21 is a recently discovered cytokine in early clinical development, which has shown anti-tumor activity in various animal models. In the present study, we examine the anti-tumor activity of IL-21 protein therapy in two syngeneic tumor models and its effect on the density of tumor infiltrating T cells. We treated mice bearing established subcutaneous B16 melanomas or RenCa renal cell carcinomas with intraperitoneal (i.p.) or subcutaneous (s.c.) IL-21 protein therapy and subsequently scored the densities of tumor infiltrating CD4(+) and CD8(+) T cells by immunohistochemistry. Whereas both routes of IL-21 administration significantly inhibited growth of small, established RenCa and B16 tumors, only s.c. therapy significantly inhibited the growth of large, established tumors. We found a greater bioavailability and significant drainage of IL-21 to regional lymph nodes following s.c. administration, which could account for the apparent increase in anti-tumor activity. Specific depletion of CD8(+) T cells with monoclonal antibodies completely abrogated the anti-tumor activity, whereas NK1.1(+) cell depletion did not affect tumor growth. In accordance, both routes of IL-21 administration significantly increased the density of tumor infiltrating CD8(+) T cells in both B16 and RenCa tumors; and in the RenCa model s.c. administration of IL-21 led to a significantly higher density of tumor infiltrating CD8(+) T cells compared to i.p. administration. The densities of CD4(+) T cells were unchanged following IL-21 treatments. Taken together, these data demonstrate that IL-21 protein has anti-tumor activity in established syngeneic tumors, and we show that IL-21 therapy markedly increases the density of tumor infiltrating CD8(+) T cells.

U2 - 10.1007/s00262-007-0285-4

DO - 10.1007/s00262-007-0285-4

M3 - Journal article

C2 - 17285290

VL - 56

SP - 1417

EP - 1428

JO - Cancer Immunology, Immunotherapy

JF - Cancer Immunology, Immunotherapy

SN - 0340-7004

IS - 9

ER -