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Dynamics of central and peripheral immunomodulation in a murine glioma model.

Kennedy BC, Maier LM, D'Amico R, Mandigo CE, Fontana EJ, Waziri A, Assanah MC, Canoll P, Anderson RC, Anderson DE, Bruce JN - BMC Immunol. (2009)

Bottom Line: An increase in TIL frequency was also observed at these final time points.These data provide insight into the kinetics of the immunosuppressive state associated with tumor growth in a murine model of human gliomas.Functional impairment of TAMs occurs relatively late in the course of GBM tumor growth, potentially providing a window of opportunity for therapeutic strategies directed towards preventing their functional impairment.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurosurgery, Gabriele Bartoli Brain Tumor Research Laboratory Columbia University, New York, NY, USA. bck2104@columbia.edu

ABSTRACT

Background: Immunosuppression by gliomas contributes to tumor progression and treatment resistance. It is not known when immunosuppression occurs during tumor development but it likely involves cross-talk among tumor cells, tumor-associated macrophages and microglia (TAMs), and peripheral as well as tumor-infiltrating lymphocytes (TILs).

Results: We have performed a kinetic study of this immunomodulation, assessing the dynamics of immune infiltration and function, within the central nervous system (CNS) and peripherally. PDGF-driven murine glioma cells were injected into the white matter of 13 mice. Four mice were sacrificed 13 days post-injection (dpi), four mice at 26 dpi, and five mice at 40 dpi. Using multiparameter flow cytometry, splenic T cells were assessed for FoxP3 expression to identify regulatory T cells (Tregs) and production of IFN-gamma and IL-10 after stimulation with PMA/ionomycin; within the CNS, CD4+ TILs were quantified, and TAMs were quantified and assessed for TNF-alpha and IL-10 production after stimulation with LPS. Peripheral changes associated with tumor development were noted prior to effects within the CNS. The percentage of FoxP3+ regulatory T cells (Tregs) increased by day 26, with elevated frequencies throughout the duration of the study. This early increase in Tregs was paralleled by an increase in IL-10 production from Tregs. At the final time points examined (tumor morbidity or 40 dpi), there was an increase in the frequency of TAMs with decreased capacity to secrete TNF-alpha. An increase in TIL frequency was also observed at these final time points.

Conclusion: These data provide insight into the kinetics of the immunosuppressive state associated with tumor growth in a murine model of human gliomas. Functional impairment of TAMs occurs relatively late in the course of GBM tumor growth, potentially providing a window of opportunity for therapeutic strategies directed towards preventing their functional impairment.

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Frequency and functional changes in tumor-associated macrophages and microglia (TAMs) in ex vivo tumor specimens over the course of tumor development. While the percentage of TAMs (CD11b+CD45+ cells) was increased by the final time-point (1.1% vs. 5.6%, P = 0.017), their functional capacity was impaired as measured by TNF-a expression (25.2% vs. 10.9%, P = 0.007). 13 mice were analyzed at 13 dpi (n = 4), 26 dpi (n = 4), and at 29 dpi upon exhibiting clinical tumor morbidity (n = 1) or at 40 dpi (n = 4). Differences between the means at each time point were tested using two-sided t tests with unequal variances. *, P < 0.05; **, P < 0.01, ***, P < 0.001.
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Figure 5: Frequency and functional changes in tumor-associated macrophages and microglia (TAMs) in ex vivo tumor specimens over the course of tumor development. While the percentage of TAMs (CD11b+CD45+ cells) was increased by the final time-point (1.1% vs. 5.6%, P = 0.017), their functional capacity was impaired as measured by TNF-a expression (25.2% vs. 10.9%, P = 0.007). 13 mice were analyzed at 13 dpi (n = 4), 26 dpi (n = 4), and at 29 dpi upon exhibiting clinical tumor morbidity (n = 1) or at 40 dpi (n = 4). Differences between the means at each time point were tested using two-sided t tests with unequal variances. *, P < 0.05; **, P < 0.01, ***, P < 0.001.

Mentions: We again quantified the frequencies of TAMs, this time over the course of tumor growth and with the more specific APC-marker combination of CD45 and CD11b. Moreover, these cells were assessed for secretion of TNF-α and IL-10, the major immunostimulatory and immunoinhibitory cytokines from this cell population, respectively. Between the early and intermediate time points, very little change in TAM frequency was observed (2.0% vs. 1.1%). Between the intermediate and final time points, however, there was a substantial increase in frequency of TAMs (1.1% vs. 5.6%, P = 0.017) (Figure 5). Of greatest interest, there was no observed change in the proportion of TAMs secreting TNF-α ex vivo between the early and intermediate time points (24.7% vs. 25.2%), but at the late stages of tumor growth, a 2.5-fold reduction in the proportion of these TAMs expressing TNF-α was observed (25.2% vs. 10.9%, P = 0.007) (Figure 5). No changes in IL-10 expression were detected (data not shown).


Dynamics of central and peripheral immunomodulation in a murine glioma model.

Kennedy BC, Maier LM, D'Amico R, Mandigo CE, Fontana EJ, Waziri A, Assanah MC, Canoll P, Anderson RC, Anderson DE, Bruce JN - BMC Immunol. (2009)

Frequency and functional changes in tumor-associated macrophages and microglia (TAMs) in ex vivo tumor specimens over the course of tumor development. While the percentage of TAMs (CD11b+CD45+ cells) was increased by the final time-point (1.1% vs. 5.6%, P = 0.017), their functional capacity was impaired as measured by TNF-a expression (25.2% vs. 10.9%, P = 0.007). 13 mice were analyzed at 13 dpi (n = 4), 26 dpi (n = 4), and at 29 dpi upon exhibiting clinical tumor morbidity (n = 1) or at 40 dpi (n = 4). Differences between the means at each time point were tested using two-sided t tests with unequal variances. *, P < 0.05; **, P < 0.01, ***, P < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2654428&req=5

Figure 5: Frequency and functional changes in tumor-associated macrophages and microglia (TAMs) in ex vivo tumor specimens over the course of tumor development. While the percentage of TAMs (CD11b+CD45+ cells) was increased by the final time-point (1.1% vs. 5.6%, P = 0.017), their functional capacity was impaired as measured by TNF-a expression (25.2% vs. 10.9%, P = 0.007). 13 mice were analyzed at 13 dpi (n = 4), 26 dpi (n = 4), and at 29 dpi upon exhibiting clinical tumor morbidity (n = 1) or at 40 dpi (n = 4). Differences between the means at each time point were tested using two-sided t tests with unequal variances. *, P < 0.05; **, P < 0.01, ***, P < 0.001.
Mentions: We again quantified the frequencies of TAMs, this time over the course of tumor growth and with the more specific APC-marker combination of CD45 and CD11b. Moreover, these cells were assessed for secretion of TNF-α and IL-10, the major immunostimulatory and immunoinhibitory cytokines from this cell population, respectively. Between the early and intermediate time points, very little change in TAM frequency was observed (2.0% vs. 1.1%). Between the intermediate and final time points, however, there was a substantial increase in frequency of TAMs (1.1% vs. 5.6%, P = 0.017) (Figure 5). Of greatest interest, there was no observed change in the proportion of TAMs secreting TNF-α ex vivo between the early and intermediate time points (24.7% vs. 25.2%), but at the late stages of tumor growth, a 2.5-fold reduction in the proportion of these TAMs expressing TNF-α was observed (25.2% vs. 10.9%, P = 0.007) (Figure 5). No changes in IL-10 expression were detected (data not shown).

Bottom Line: An increase in TIL frequency was also observed at these final time points.These data provide insight into the kinetics of the immunosuppressive state associated with tumor growth in a murine model of human gliomas.Functional impairment of TAMs occurs relatively late in the course of GBM tumor growth, potentially providing a window of opportunity for therapeutic strategies directed towards preventing their functional impairment.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurosurgery, Gabriele Bartoli Brain Tumor Research Laboratory Columbia University, New York, NY, USA. bck2104@columbia.edu

ABSTRACT

Background: Immunosuppression by gliomas contributes to tumor progression and treatment resistance. It is not known when immunosuppression occurs during tumor development but it likely involves cross-talk among tumor cells, tumor-associated macrophages and microglia (TAMs), and peripheral as well as tumor-infiltrating lymphocytes (TILs).

Results: We have performed a kinetic study of this immunomodulation, assessing the dynamics of immune infiltration and function, within the central nervous system (CNS) and peripherally. PDGF-driven murine glioma cells were injected into the white matter of 13 mice. Four mice were sacrificed 13 days post-injection (dpi), four mice at 26 dpi, and five mice at 40 dpi. Using multiparameter flow cytometry, splenic T cells were assessed for FoxP3 expression to identify regulatory T cells (Tregs) and production of IFN-gamma and IL-10 after stimulation with PMA/ionomycin; within the CNS, CD4+ TILs were quantified, and TAMs were quantified and assessed for TNF-alpha and IL-10 production after stimulation with LPS. Peripheral changes associated with tumor development were noted prior to effects within the CNS. The percentage of FoxP3+ regulatory T cells (Tregs) increased by day 26, with elevated frequencies throughout the duration of the study. This early increase in Tregs was paralleled by an increase in IL-10 production from Tregs. At the final time points examined (tumor morbidity or 40 dpi), there was an increase in the frequency of TAMs with decreased capacity to secrete TNF-alpha. An increase in TIL frequency was also observed at these final time points.

Conclusion: These data provide insight into the kinetics of the immunosuppressive state associated with tumor growth in a murine model of human gliomas. Functional impairment of TAMs occurs relatively late in the course of GBM tumor growth, potentially providing a window of opportunity for therapeutic strategies directed towards preventing their functional impairment.

Show MeSH
Related in: MedlinePlus