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In situ modulation of dendritic cells by injectable thermosensitive hydrogels for cancer vaccines in mice.

Liu Y, Xiao L, Joo KI, Hu B, Fang J, Wang P - Biomacromolecules (2014)

Bottom Line: Attempts to develop cell-based cancer vaccines have shown limited efficacy, partly because transplanted dendritic cells (DCs) do not survive long enough to reach the lymph nodes.We demonstrate that GM-CSF-releasing mPEG-PLGA hydrogels successfully recruit and house DCs and macrophages, allowing the subsequent introduction of antigens by vectors to activate the resident cells, thus, initiating antigen presentation and triggering immune response.This injectable thermosensitive hydrogel shows great promise as an adjuvant for cancer vaccines, potentially providing a new approach for cell therapies through in situ modulation of cells.

View Article: PubMed Central - PubMed

Affiliation: Mork Family Department of Chemical Engineering and Materials Science, ‡Department of Biomedical Engineering, and §Department of Pharmacology and Pharmaceutical Sciences, University of Southern California , Los Angeles, California 90089, United States.

ABSTRACT
Attempts to develop cell-based cancer vaccines have shown limited efficacy, partly because transplanted dendritic cells (DCs) do not survive long enough to reach the lymph nodes. The development of biomaterials capable of modulating DCs in situ to enhance antigen uptake and presentation has emerged as a novel method toward developing more efficient cancer vaccines. Here, we propose a two-step hybrid strategy to produce a more robust cell-based cancer vaccine in situ. First, a significant number of DCs are recruited to an injectable thermosensitive mPEG-PLGA hydrogel through sustained release of chemoattractants, in particular, granulocyte-macrophage colony-stimulating factor (GM-CSF). Then, these resident DCs can be loaded with cancer antigens through the use of viral or nonviral vectors. We demonstrate that GM-CSF-releasing mPEG-PLGA hydrogels successfully recruit and house DCs and macrophages, allowing the subsequent introduction of antigens by vectors to activate the resident cells, thus, initiating antigen presentation and triggering immune response. Moreover, this two-step hybrid strategy generates a high level of tumor-specific immunity, as demonstrated in both prophylactic and therapeutic models of murine melanoma. This injectable thermosensitive hydrogel shows great promise as an adjuvant for cancer vaccines, potentially providing a new approach for cell therapies through in situ modulation of cells.

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GM-hydrogel allows for further modulation of residentDCs by adjuvantsto enhance immune responses against specific antigen (OVA). (A) Invitro effects of adjuvants MPL and CpG on maturation of BMDCs. BMDCswere stimulated with 1 μg/mL MPL or 5 μM CpG overnight.The BMDCs were collected for staining of CD11c, I-Ab, CD54,and CD86. The result was analyzed by flow cytometry, and the expressionof surface markers I-Ab, CD54, and CD86 was gated on CD11c+ DCs. (B) Schematic diagram showing the procedures. Sevendays after injection of hydrogels with 5 μg of GM-CSF, micewere immunized with DC-LV-OVA. One day after immunization, the micewere injected with adjuvants (CpG or MPL). Two weeks after immunization,splenocytes were collected, and OVA-specific CD8+ T cellswere analyzed by intracellular staining of IFN-γ expression.(C, D) GM-CSF hydrogels enable further enhancement of lentiviral vector-mediatedimmune responses with adjuvants. The FACS data are representativeof four analyzed mice (C). Statistical data showing the percentageof IFN-γ+ cells within the CD8+ T cellpopulation (D). (F) The effect of GM-CSF-loaded hydrogels on nonviralvector-mediated immune response. Seven days after injection of hydrogelswith 5 μg of GM-CSF, mice were immunized with OVA protein andMPL. Seven days after immunization, splenocytes were pooled for anELISPOT assay to analyze IL-2 secretion following stimulation withpeptide for 18 h (n = 3).
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fig4: GM-hydrogel allows for further modulation of residentDCs by adjuvantsto enhance immune responses against specific antigen (OVA). (A) Invitro effects of adjuvants MPL and CpG on maturation of BMDCs. BMDCswere stimulated with 1 μg/mL MPL or 5 μM CpG overnight.The BMDCs were collected for staining of CD11c, I-Ab, CD54,and CD86. The result was analyzed by flow cytometry, and the expressionof surface markers I-Ab, CD54, and CD86 was gated on CD11c+ DCs. (B) Schematic diagram showing the procedures. Sevendays after injection of hydrogels with 5 μg of GM-CSF, micewere immunized with DC-LV-OVA. One day after immunization, the micewere injected with adjuvants (CpG or MPL). Two weeks after immunization,splenocytes were collected, and OVA-specific CD8+ T cellswere analyzed by intracellular staining of IFN-γ expression.(C, D) GM-CSF hydrogels enable further enhancement of lentiviral vector-mediatedimmune responses with adjuvants. The FACS data are representativeof four analyzed mice (C). Statistical data showing the percentageof IFN-γ+ cells within the CD8+ T cellpopulation (D). (F) The effect of GM-CSF-loaded hydrogels on nonviralvector-mediated immune response. Seven days after injection of hydrogelswith 5 μg of GM-CSF, mice were immunized with OVA protein andMPL. Seven days after immunization, splenocytes were pooled for anELISPOT assay to analyze IL-2 secretion following stimulation withpeptide for 18 h (n = 3).

Mentions: We next asked whether the activation and maturation of DCswithmolecular adjuvant could further enhance the immune response in thisGM-CSF hydrogel system. To test this possibility, mice were immunizedwith DC-LV-OVA 7 days postinjection with GM-CSF (5 μg) hydrogel.The effect of two adjuvants, monophosphoryl Lipid A (MPL) and CpG,on the maturation of BMDCs was first examined in vitro. Significantenhancement in the expression of surface markers, including CD54,I-Ab, and CD 86, was observed after incubating BMDCs withthe adjuvants overnight (Figure 4A). To testthe effect in vivo, either CpG or MPL was injected into the hydrogelinoculation site at day 8, and the degree of immune response was evaluatedby measuring IFN-γ production in CD8+ T cells takenfrom mice 14 days postimmunization (Figure 4B). As shown in Figure 4C,D, the GM-CSF hydrogelenabled a significant enhancement in immune responses induced by DC-LV-OVAwith CpG or MPL compared to empty hydrogel. The data suggest thatDCs recruited by GM-CSF could be further activated and maturated bythe addition of adjuvant to enhance antigen-specific immune responses.Moreover, the ability of GM-CSF hydrogel to serve as a microenvironmentfor DC recruitment and programming by nonviral antigen delivery vectorswas investigated. As shown in Figure 4E, immunizationwith OVA protein and MPL resulted in a 3-fold increase in IFN-γproduction of CD8+ cytotoxic T cells in mice bearing GM-CSFhydrogels over those bearing empty hydrogel. Taken together, thesedata suggest that GM-CSF hydrogel can recruit DCs and allow in situDC programming by antigen delivery vectors and adjuvant to increaseT cell priming.


In situ modulation of dendritic cells by injectable thermosensitive hydrogels for cancer vaccines in mice.

Liu Y, Xiao L, Joo KI, Hu B, Fang J, Wang P - Biomacromolecules (2014)

GM-hydrogel allows for further modulation of residentDCs by adjuvantsto enhance immune responses against specific antigen (OVA). (A) Invitro effects of adjuvants MPL and CpG on maturation of BMDCs. BMDCswere stimulated with 1 μg/mL MPL or 5 μM CpG overnight.The BMDCs were collected for staining of CD11c, I-Ab, CD54,and CD86. The result was analyzed by flow cytometry, and the expressionof surface markers I-Ab, CD54, and CD86 was gated on CD11c+ DCs. (B) Schematic diagram showing the procedures. Sevendays after injection of hydrogels with 5 μg of GM-CSF, micewere immunized with DC-LV-OVA. One day after immunization, the micewere injected with adjuvants (CpG or MPL). Two weeks after immunization,splenocytes were collected, and OVA-specific CD8+ T cellswere analyzed by intracellular staining of IFN-γ expression.(C, D) GM-CSF hydrogels enable further enhancement of lentiviral vector-mediatedimmune responses with adjuvants. The FACS data are representativeof four analyzed mice (C). Statistical data showing the percentageof IFN-γ+ cells within the CD8+ T cellpopulation (D). (F) The effect of GM-CSF-loaded hydrogels on nonviralvector-mediated immune response. Seven days after injection of hydrogelswith 5 μg of GM-CSF, mice were immunized with OVA protein andMPL. Seven days after immunization, splenocytes were pooled for anELISPOT assay to analyze IL-2 secretion following stimulation withpeptide for 18 h (n = 3).
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Related In: Results  -  Collection

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fig4: GM-hydrogel allows for further modulation of residentDCs by adjuvantsto enhance immune responses against specific antigen (OVA). (A) Invitro effects of adjuvants MPL and CpG on maturation of BMDCs. BMDCswere stimulated with 1 μg/mL MPL or 5 μM CpG overnight.The BMDCs were collected for staining of CD11c, I-Ab, CD54,and CD86. The result was analyzed by flow cytometry, and the expressionof surface markers I-Ab, CD54, and CD86 was gated on CD11c+ DCs. (B) Schematic diagram showing the procedures. Sevendays after injection of hydrogels with 5 μg of GM-CSF, micewere immunized with DC-LV-OVA. One day after immunization, the micewere injected with adjuvants (CpG or MPL). Two weeks after immunization,splenocytes were collected, and OVA-specific CD8+ T cellswere analyzed by intracellular staining of IFN-γ expression.(C, D) GM-CSF hydrogels enable further enhancement of lentiviral vector-mediatedimmune responses with adjuvants. The FACS data are representativeof four analyzed mice (C). Statistical data showing the percentageof IFN-γ+ cells within the CD8+ T cellpopulation (D). (F) The effect of GM-CSF-loaded hydrogels on nonviralvector-mediated immune response. Seven days after injection of hydrogelswith 5 μg of GM-CSF, mice were immunized with OVA protein andMPL. Seven days after immunization, splenocytes were pooled for anELISPOT assay to analyze IL-2 secretion following stimulation withpeptide for 18 h (n = 3).
Mentions: We next asked whether the activation and maturation of DCswithmolecular adjuvant could further enhance the immune response in thisGM-CSF hydrogel system. To test this possibility, mice were immunizedwith DC-LV-OVA 7 days postinjection with GM-CSF (5 μg) hydrogel.The effect of two adjuvants, monophosphoryl Lipid A (MPL) and CpG,on the maturation of BMDCs was first examined in vitro. Significantenhancement in the expression of surface markers, including CD54,I-Ab, and CD 86, was observed after incubating BMDCs withthe adjuvants overnight (Figure 4A). To testthe effect in vivo, either CpG or MPL was injected into the hydrogelinoculation site at day 8, and the degree of immune response was evaluatedby measuring IFN-γ production in CD8+ T cells takenfrom mice 14 days postimmunization (Figure 4B). As shown in Figure 4C,D, the GM-CSF hydrogelenabled a significant enhancement in immune responses induced by DC-LV-OVAwith CpG or MPL compared to empty hydrogel. The data suggest thatDCs recruited by GM-CSF could be further activated and maturated bythe addition of adjuvant to enhance antigen-specific immune responses.Moreover, the ability of GM-CSF hydrogel to serve as a microenvironmentfor DC recruitment and programming by nonviral antigen delivery vectorswas investigated. As shown in Figure 4E, immunizationwith OVA protein and MPL resulted in a 3-fold increase in IFN-γproduction of CD8+ cytotoxic T cells in mice bearing GM-CSFhydrogels over those bearing empty hydrogel. Taken together, thesedata suggest that GM-CSF hydrogel can recruit DCs and allow in situDC programming by antigen delivery vectors and adjuvant to increaseT cell priming.

Bottom Line: Attempts to develop cell-based cancer vaccines have shown limited efficacy, partly because transplanted dendritic cells (DCs) do not survive long enough to reach the lymph nodes.We demonstrate that GM-CSF-releasing mPEG-PLGA hydrogels successfully recruit and house DCs and macrophages, allowing the subsequent introduction of antigens by vectors to activate the resident cells, thus, initiating antigen presentation and triggering immune response.This injectable thermosensitive hydrogel shows great promise as an adjuvant for cancer vaccines, potentially providing a new approach for cell therapies through in situ modulation of cells.

View Article: PubMed Central - PubMed

Affiliation: Mork Family Department of Chemical Engineering and Materials Science, ‡Department of Biomedical Engineering, and §Department of Pharmacology and Pharmaceutical Sciences, University of Southern California , Los Angeles, California 90089, United States.

ABSTRACT
Attempts to develop cell-based cancer vaccines have shown limited efficacy, partly because transplanted dendritic cells (DCs) do not survive long enough to reach the lymph nodes. The development of biomaterials capable of modulating DCs in situ to enhance antigen uptake and presentation has emerged as a novel method toward developing more efficient cancer vaccines. Here, we propose a two-step hybrid strategy to produce a more robust cell-based cancer vaccine in situ. First, a significant number of DCs are recruited to an injectable thermosensitive mPEG-PLGA hydrogel through sustained release of chemoattractants, in particular, granulocyte-macrophage colony-stimulating factor (GM-CSF). Then, these resident DCs can be loaded with cancer antigens through the use of viral or nonviral vectors. We demonstrate that GM-CSF-releasing mPEG-PLGA hydrogels successfully recruit and house DCs and macrophages, allowing the subsequent introduction of antigens by vectors to activate the resident cells, thus, initiating antigen presentation and triggering immune response. Moreover, this two-step hybrid strategy generates a high level of tumor-specific immunity, as demonstrated in both prophylactic and therapeutic models of murine melanoma. This injectable thermosensitive hydrogel shows great promise as an adjuvant for cancer vaccines, potentially providing a new approach for cell therapies through in situ modulation of cells.

Show MeSH
Related in: MedlinePlus