CD4+CD25+ T regulatory (Treg) cells were initially described for their ability to suppress autoimmune diseases in animal models. An emerging interest is the potential role of Treg cells in cancer development and progression because they have been shown to suppress antitumor immunity. In this study, CD4+CD25− T cells cultured in conditioned medium (CM) derived from tumor cells, RENCA or TRAMP-C2, possess similar characteristics as those of naturally occurring Treg cells, including expression of Foxp3, a crucial transcription factor of Treg cells, production of low levels of IL-2, high levels of IL-10 and TGF-β, and the ability to suppress CD4+CD25− T cell proliferation. Further investigation revealed a critical role of tumor-derived TGF-β in converting CD4+CD25− T cells into Treg cells because a neutralizing Ab against TGF-β, 1D11, completely abrogated the induction of Treg cells. CM from a nontumorigenic cell line, NRP-152, or irradiated tumor cells did not convert CD4+CD25− T cells to Treg cells because they produce low levels of TGF-β in CM. Finally, we observed a reduced tumor burden in animals receiving 1D11. The reduction in tumor burden correlated with a decrease in tumor-derived TGF-β. Treatment of 1D11 also reduced the conversion of CD4+ T cells into Treg cells and subsequent Treg cell-mediated suppression of antitumor immunity. In summary, we have demonstrated that tumor cells directly convert CD4+CD25− T cells to Treg cells through production of high levels of TGF-β, suggesting a possible mechanism through which tumor cells evade the immune system.
Our study has identified a unique mechanism that describes how components of pathogens common in the urinary system may contribute to the malignant transformation of benign prostate epithelia.
The etiology of chronic prostatitis/chronic pelvic pain syndrome in men is unknown but may involve microbes and autoimmune mechanisms. We developed an infection model of chronic pelvic pain in NOD/ShiLtJ (NOD) mice with a clinical Escherichia coli isolate (CP-1) from a patient with chronic pelvic pain. We investigated pain mechanisms in NOD mice and compared it to C57BL/6 (B6) mice, a strain resistant to CP-1-induced pain. Adoptive transfer of CD4+ T cells, but not serum, from CP-1-infected NOD mice was sufficient to induce chronic pelvic pain. CD4+ T cells in CP-1-infected NOD mice expressed IFN-γ and IL-17A but not IL-4, consistent with a Th1/Th17 immune signature. Adoptive transfer of ex-vivo expanded IFN-γ or IL-17A-expressing cells was sufficient to induce pelvic pain in naïve NOD recipients. Pelvic pain was not abolished in NOD-IFN-γ-KO mice but was associated with an enhanced IL-17A immune response to CP1 infection. These findings demonstrate a novel role for Th1 and Th17-mediated adaptive immune mechanisms in chronic pelvic pain.
Chronic pelvic pain syndrome (CPPS) is the most common form of prostatitis, accounting for 90–95% of all diagnoses. It is a complex multi-symptom syndrome with unknown etiology and limited effective treatments. Previous investigations highlight roles for inflammatory mediators in disease progression by correlating levels of cytokines and chemokines with patient reported symptom scores. It is hypothesized that alteration of adaptive immune mechanisms results in autoimmunity and subsequent development of pain. Mouse models of CPPS have been developed to delineate these immune mechanisms driving pain in humans. Using the experimental autoimmune prostatitis (EAP) in C57BL/6 mice model of CPPS we examined the role of CD4+T-cell subsets in the development and maintenance of prostate pain, by tactile allodynia behavioral testing and flow cytometry. In tandem with increased CD4+IL17A+ T-cells upon EAP induction, prophylactic treatment with an anti-IL17 antibody one-day prior to EAP induction prevented the onset of pelvic pain. Therapeutic blockade of IL17 did not reverse pain symptoms indicating that IL17 is essential for development but not maintenance of chronic pain in EAP. Furthermore we identified a cytokine, IL7, to be associated with increased symptom severity in CPPS patients and is increased in patient prostatic secretions and the prostates of EAP mice. IL7 is fundamental to development of IL17 producing cells and plays a role in maturation of auto-reactive T-cells, it is also associated with autoimmune disorders including multiple sclerosis and type-1 diabetes. More recently a growing body of research has pointed to IL17’s role in development of neuropathic and chronic pain. This report presents novel data on the role of CD4+IL17+ T-cells in development and maintenance of pain in EAP and CPPS.
Background
The pathogenesis of chronic prostatitis/chronic pelvic pain syndrome is unknown and factors including the host’s immune response and the nervous system have been attributed to the development of CP/CPPS. We previously demonstrated that mast cells and chemokines such as CCL2 and CCL3 play an important role in mediating prostatitis. Here, we examined the role of neuroinflammation and microglia in the CNS in the development of chronic pelvic pain.
Methods
Experimental autoimmune prostatitis (EAP) was induced using a subcutaneous injection of rat prostate antigen. Sacral spinal cord tissue (segments S4–S5) was isolated and utilized for immunofluorescence or QRT-PCR analysis. Tactile allodynia was measured at baseline and at various points during EAP using Von Frey fibers as a function for pelvic pain. EAP mice were treated with minocycline after 30 days of prostatitis to test the efficacy of microglial inhibition on pelvic pain.
Results
Prostatitis induced the expansion and activation of microglia and the development of inflammation in the spinal cord as determined by increased expression levels of CCL3, IL-1β, Iba1, and ERK1/2 phosphorylation. Microglial activation in mice with prostatitis resulted in increased expression of P2X4R and elevated levels of BDNF, two molecular markers associated with chronic pain. Pharmacological inhibition of microglia alleviated pain in mice with prostatitis and resulted in decreased expression of IL-1β, P2X4R, and BDNF.
Conclusion
Our data shows that prostatitis leads to inflammation in the spinal cord and the activation and expansion of microglia, mechanisms that may contribute to the development and maintenance of chronic pelvic pain.
Our results demonstrate the mechanism of anti-tumor effect of tumor-reactive TGF-beta-insensitive CD8+ T cells that adoptive transfer of these CD8+ T cells resulted in infiltration of these immune cells into the tumor parenchyma, secretion of relevant cytokines, and induction of apoptosis in tumor cells. These results support the concept that tumor-reactive TGF-beta-insensitive CD8+ T cells may prove beneficial in the treatment of advanced cancer patients.
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