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In vivo microRNA-155 expression influences antigen-specific T cell-mediated immune responses generated by DNA vaccination.

Mao CP, He L, Tsai YC, Peng S, Kang TH, Pang X, Monie A, Hung CF, Wu TC - Cell Biosci (2011)

Bottom Line: Biolistic epidermal transfection with DNA encoding miR-155 suppressed the induction of antigen-specific T cell-mediated immunity, whereas reduction of endogenous miR-155 by a partially complementary antisense sequence reversed this effect.Because DCs represent a significant component of epidermal tissue and are among the most potent of antigen-presenting cells, the inhibitory actions of miR-155 could be mediated through this subset of cells.These results suggest that miR-155 may repress the expression of key molecules involved in lymph node migration, antigen presentation, or T cell activation in DCs, and thus forms part of a negative regulatory pathway that dampens the generation of T cell-mediated immune responses.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA. wutc@jhmi.edu.

ABSTRACT

Background: MicroRNA (miRNA) molecules are potent mediators of post-transcriptional gene silencing that are emerging to be critical in the regulation of innate and adaptive immunity.

Results: Here we report that miR-155--an oncogenic miRNA with important function in the mammalian immune system--is induced in dendritic cells (DCs) upon maturation and potentially attenuates their ability to activate T cells. Biolistic epidermal transfection with DNA encoding miR-155 suppressed the induction of antigen-specific T cell-mediated immunity, whereas reduction of endogenous miR-155 by a partially complementary antisense sequence reversed this effect. Because DCs represent a significant component of epidermal tissue and are among the most potent of antigen-presenting cells, the inhibitory actions of miR-155 could be mediated through this subset of cells.

Conclusions: These results suggest that miR-155 may repress the expression of key molecules involved in lymph node migration, antigen presentation, or T cell activation in DCs, and thus forms part of a negative regulatory pathway that dampens the generation of T cell-mediated immune responses. Modulation of miR-155 expression in epidermis therefore represents a potentially promising form of gene therapy for the control of diseases ranging from autoimmunity to cancer and viral infection.

No MeSH data available.


Related in: MedlinePlus

Characterization of the number of E7-specific IFN-γ CD8+ T cells in mice vaccinated intradermally with CRT/E7 DNA in combination with bic155 , I155, or a control construct. C57BL/6 mice (3 per group) were immunized with CRT/E7 in combination with bic155, I155, or a control construct. At day 7, animals received boosters at the same dose and regimen. At day 14, splenocytes were harvested, cultured for 15 hrs with (black bars) or without (grey bars) E7 peptide, and stained for surface CD8 and intracellular IFN-γ. Cells were analyzed by flow cytometry. A, Representative flow cytometry data depicting the number of E7-specific CD8+ T cells. B, Bar graph representation of the flow cytometry data (mean ± SD). The y-axis on the bar graph depicts the number of IFN-γ-secreting E7-specific CD8+ T cells per 3 × 105 counted splenocytes (mean ± SD).
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Figure 5: Characterization of the number of E7-specific IFN-γ CD8+ T cells in mice vaccinated intradermally with CRT/E7 DNA in combination with bic155 , I155, or a control construct. C57BL/6 mice (3 per group) were immunized with CRT/E7 in combination with bic155, I155, or a control construct. At day 7, animals received boosters at the same dose and regimen. At day 14, splenocytes were harvested, cultured for 15 hrs with (black bars) or without (grey bars) E7 peptide, and stained for surface CD8 and intracellular IFN-γ. Cells were analyzed by flow cytometry. A, Representative flow cytometry data depicting the number of E7-specific CD8+ T cells. B, Bar graph representation of the flow cytometry data (mean ± SD). The y-axis on the bar graph depicts the number of IFN-γ-secreting E7-specific CD8+ T cells per 3 × 105 counted splenocytes (mean ± SD).

Mentions: We hypothesized that, since bic155 strongly attenuated the T cell-mediated immune response in CRT/E7-vaccinated mice, an inhibitor of miR-155, I155, would reverse this effect. C57BL/6 mice were intradermally administered by gene gun with CRT/E7 in combination with bic155, I155, or a control construct. Animals were boosted with the same dose and regimen on day 7. Splenocytes were harvested on day 14 and then characterized for E7-specific CD8+ T cell-mediated immune responses by intracellular IFN-γ and surface CD8 staining followed by flow cytometry analysis. As shown in Figure 5, while coadministration of bic155 with CRT/E7 DNA decreased the number of IFN-γ-secreting E7-specific cytotoxic T cells generated by CRT/E7 (* p < 0.01), coadministration of I155 with CRT/E7 DNA significantly improved the E7-specific CD8+ T cell-mediated immune response generated by CRT/E7 (** p < 0.05). Altogether, our data indicate that modulation of expression levels of miR-155 can influence the ability of DCs to prime antigen-specific naïve T cells in vivo. Furthermore, these results suggest that miR-155 may act broadly as a post-transcriptional silencer in negative feedback pathways that dampen the adaptive immune response following the initial phases of T cell activation.


In vivo microRNA-155 expression influences antigen-specific T cell-mediated immune responses generated by DNA vaccination.

Mao CP, He L, Tsai YC, Peng S, Kang TH, Pang X, Monie A, Hung CF, Wu TC - Cell Biosci (2011)

Characterization of the number of E7-specific IFN-γ CD8+ T cells in mice vaccinated intradermally with CRT/E7 DNA in combination with bic155 , I155, or a control construct. C57BL/6 mice (3 per group) were immunized with CRT/E7 in combination with bic155, I155, or a control construct. At day 7, animals received boosters at the same dose and regimen. At day 14, splenocytes were harvested, cultured for 15 hrs with (black bars) or without (grey bars) E7 peptide, and stained for surface CD8 and intracellular IFN-γ. Cells were analyzed by flow cytometry. A, Representative flow cytometry data depicting the number of E7-specific CD8+ T cells. B, Bar graph representation of the flow cytometry data (mean ± SD). The y-axis on the bar graph depicts the number of IFN-γ-secreting E7-specific CD8+ T cells per 3 × 105 counted splenocytes (mean ± SD).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3116247&req=5

Figure 5: Characterization of the number of E7-specific IFN-γ CD8+ T cells in mice vaccinated intradermally with CRT/E7 DNA in combination with bic155 , I155, or a control construct. C57BL/6 mice (3 per group) were immunized with CRT/E7 in combination with bic155, I155, or a control construct. At day 7, animals received boosters at the same dose and regimen. At day 14, splenocytes were harvested, cultured for 15 hrs with (black bars) or without (grey bars) E7 peptide, and stained for surface CD8 and intracellular IFN-γ. Cells were analyzed by flow cytometry. A, Representative flow cytometry data depicting the number of E7-specific CD8+ T cells. B, Bar graph representation of the flow cytometry data (mean ± SD). The y-axis on the bar graph depicts the number of IFN-γ-secreting E7-specific CD8+ T cells per 3 × 105 counted splenocytes (mean ± SD).
Mentions: We hypothesized that, since bic155 strongly attenuated the T cell-mediated immune response in CRT/E7-vaccinated mice, an inhibitor of miR-155, I155, would reverse this effect. C57BL/6 mice were intradermally administered by gene gun with CRT/E7 in combination with bic155, I155, or a control construct. Animals were boosted with the same dose and regimen on day 7. Splenocytes were harvested on day 14 and then characterized for E7-specific CD8+ T cell-mediated immune responses by intracellular IFN-γ and surface CD8 staining followed by flow cytometry analysis. As shown in Figure 5, while coadministration of bic155 with CRT/E7 DNA decreased the number of IFN-γ-secreting E7-specific cytotoxic T cells generated by CRT/E7 (* p < 0.01), coadministration of I155 with CRT/E7 DNA significantly improved the E7-specific CD8+ T cell-mediated immune response generated by CRT/E7 (** p < 0.05). Altogether, our data indicate that modulation of expression levels of miR-155 can influence the ability of DCs to prime antigen-specific naïve T cells in vivo. Furthermore, these results suggest that miR-155 may act broadly as a post-transcriptional silencer in negative feedback pathways that dampen the adaptive immune response following the initial phases of T cell activation.

Bottom Line: Biolistic epidermal transfection with DNA encoding miR-155 suppressed the induction of antigen-specific T cell-mediated immunity, whereas reduction of endogenous miR-155 by a partially complementary antisense sequence reversed this effect.Because DCs represent a significant component of epidermal tissue and are among the most potent of antigen-presenting cells, the inhibitory actions of miR-155 could be mediated through this subset of cells.These results suggest that miR-155 may repress the expression of key molecules involved in lymph node migration, antigen presentation, or T cell activation in DCs, and thus forms part of a negative regulatory pathway that dampens the generation of T cell-mediated immune responses.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA. wutc@jhmi.edu.

ABSTRACT

Background: MicroRNA (miRNA) molecules are potent mediators of post-transcriptional gene silencing that are emerging to be critical in the regulation of innate and adaptive immunity.

Results: Here we report that miR-155--an oncogenic miRNA with important function in the mammalian immune system--is induced in dendritic cells (DCs) upon maturation and potentially attenuates their ability to activate T cells. Biolistic epidermal transfection with DNA encoding miR-155 suppressed the induction of antigen-specific T cell-mediated immunity, whereas reduction of endogenous miR-155 by a partially complementary antisense sequence reversed this effect. Because DCs represent a significant component of epidermal tissue and are among the most potent of antigen-presenting cells, the inhibitory actions of miR-155 could be mediated through this subset of cells.

Conclusions: These results suggest that miR-155 may repress the expression of key molecules involved in lymph node migration, antigen presentation, or T cell activation in DCs, and thus forms part of a negative regulatory pathway that dampens the generation of T cell-mediated immune responses. Modulation of miR-155 expression in epidermis therefore represents a potentially promising form of gene therapy for the control of diseases ranging from autoimmunity to cancer and viral infection.

No MeSH data available.


Related in: MedlinePlus