Interleukin-10 production by tumor infiltrating macrophages plays a role in Human Papillomavirus 16 tumor growth

Author(s)

Bolpetti, Aline ^[1] ; Silva, Joao S. ^[2] ; Villa, Luisa L. ^[3] ; Lepique, Ana Paula ^[3]

Affiliation

^[1] Fundacao Antonio Prudente, BR-01509010 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Biochem & Immunol, BR-14049900 Ribeirao Preto, SP - Brazil

^[3] Ludwig Inst Canc Res, BR-01323903 Sao Paulo - Brazil

• Document type: Journal article
• Source: BMC IMMUNOLOGY; v. 11, JUN 7 2010.
• Web of Science Citations: 47

Abstract

Background: Human Papillomavirus, HPV, is the main etiological factor for cervical cancer. Different studies show that in women infected with HPV there is a positive correlation between lesion grade and number of infiltrating macrophages, as well as with IL-10 higher expression. Using a HPV16 associated tumor model in mice, TC-1, our laboratory has demonstrated that tumor infiltrating macrophages are M2-like, induce T cell regulatory phenotype and play an important role in tumor growth. M2 macrophages secrete several cytokines, among them IL-10, which has been shown to play a role in T cell suppression by tumor macrophages in other tumor models. In this work, we sought to establish if IL-10 is part of the mechanism by which HPV tumor associated macrophages induce T cell regulatory phenotype, inhibiting anti-tumor activity and facilitating tumor growth. Results: TC-1 tumor cells do not express or respond to IL-10, but recruit leukocytes which, within the tumor environment, produce this cytokine. Using IL-10 deficient mice or blocking IL-10 signaling with neutralizing antibodies, we observed a significant reduction in tumor growth, an increase in tumor infiltration by HPV16 E7 specific CD8 lymphocytes, including a population positive for Granzyme B and Perforin expression, and a decrease in the percentage of HPV specific regulatory T cells in the lymph nodes. Conclusions: Our data shows that in the HPV16 TC-1 tumor mouse model, IL-10 produced by tumor macrophages induce regulatory phenotype on T cells, an immune escape mechanism that facilitates tumor growth. Our results point to a possible mechanism behind the epidemiologic data that correlates higher IL-10 expression with risk of cervical cancer development in HPV infected women. (AU)