Interleukin-10 production by tumor infiltrating macrophages plays a role in Human Papillomavirus 16 tumor growth.
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.
Ludwig Institute for Cancer Research, Rua João Julião, 245, 1o andar, São Paulo, SP, 01323-903, Brazil.
Aline
A
Bolpetti
João S
JS
Silva
Luisa L
LL
Villa
Ana Paula
AP
Lepique
D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology; D002453:Cell Cycle; D002465:Cell Movement; D049109:Cell Proliferation; D052162:Human papillomavirus 16 / Q000276:immunology*; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis*; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009369:Neoplasms / Q000276:immunology / Q000473:pathology* / Q000821:virology*; D010641:Phenotype; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
D057134:Antibodies, Neutralizing; D000951:Antigens, Neoplasm; D016753:Interleukin-10