Limits...
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.

Show MeSH

Related in: MedlinePlus

Optimization of the two-step hybrid strategy to induceantigen-specificimmune responses. (A) Schematic representation showing immunizationprocedures. Mice were immunized with DC-LV-OVA at different time pointsafter GM-CSF hydrogel injection. (B) Flow cytometric analysis of IFN-γ+ cells within the CD8+ T-cell population in mousesplenocytes. (C) Quantitative data of the percentage of IFN-γ+ cells within the CD8+ T-cell population. (D, E)The effect of different doses of GM-CSF encapsulated in hydrogelson DC-LV-OVA-based vaccine-specific T cell immune responses in vivo.Seven days after injection of hydrogels with different doses of GM-CSF,mice were immunized with DC-LV-OVA. A total of 14 days later, splenocyteswere collected, and OVA-specific CD8+ T cells were analyzedby intracellular staining for IFN-γ expression after stimulationwith OVA257–264 peptide for 6 h. The FACS data arerepresentative of four analyzed mice (D). Statistical data showingthe percentage of IFN-γ+ cells within the CD8+ T cell population (E).
© Copyright Policy - editor-choice
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4195289&req=5

fig3: Optimization of the two-step hybrid strategy to induceantigen-specificimmune responses. (A) Schematic representation showing immunizationprocedures. Mice were immunized with DC-LV-OVA at different time pointsafter GM-CSF hydrogel injection. (B) Flow cytometric analysis of IFN-γ+ cells within the CD8+ T-cell population in mousesplenocytes. (C) Quantitative data of the percentage of IFN-γ+ cells within the CD8+ T-cell population. (D, E)The effect of different doses of GM-CSF encapsulated in hydrogelson DC-LV-OVA-based vaccine-specific T cell immune responses in vivo.Seven days after injection of hydrogels with different doses of GM-CSF,mice were immunized with DC-LV-OVA. A total of 14 days later, splenocyteswere collected, and OVA-specific CD8+ T cells were analyzedby intracellular staining for IFN-γ expression after stimulationwith OVA257–264 peptide for 6 h. The FACS data arerepresentative of four analyzed mice (D). Statistical data showingthe percentage of IFN-γ+ cells within the CD8+ T cell population (E).

Mentions: The local recruitmentof immature DCs and macrophages by GM-CSFhydrogel allows for larger numbers of cells to be further modulatedwith antigen delivery vectors in situ. To test this hypothesis, previouslyreported SVGmu-pseudotyped lentiviral vectors encoding ovalbumin (OVA),22,28 which can target antigen delivery to DCs, were introduced to thesite of the hydrogel after DC recruitment. First, the optimal timegap between injection of GM-CSF hydrogel and immunization with vectorscarrying OVA (DC-LV-OVA) was determined (Figure 3A). Significantly more inflammatory cytokine interferon-γ (IFN-γ)was produced by CD8+ T cells from mice immunized by DC-LV-OVA7 days postinjection of GM-CSF hydrogel than at other times (Figure 3B,C), suggesting that this immunization schedulewas optimal for further study. The optimal dose of GM-CSF exposureto recruited DCs was also evaluated by measuring the degree of immuneresponses in mice injected with hydrogels encapsulating various amountsof GM-CSF. As shown in Figure 3D,E, the highestimmune response was found in mice injected with hydrogel encapsulating5 μg of GM-CSF. A higher concentration of GM-CSF (15 and 45μg) in hydrogel led to a decrease in IFN-γ production,suggesting that an optimal GM-CSF concentration is required to recruitand subsequently disperse the activated DCs to lymph nodes for immuneresponse induction.


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)

Optimization of the two-step hybrid strategy to induceantigen-specificimmune responses. (A) Schematic representation showing immunizationprocedures. Mice were immunized with DC-LV-OVA at different time pointsafter GM-CSF hydrogel injection. (B) Flow cytometric analysis of IFN-γ+ cells within the CD8+ T-cell population in mousesplenocytes. (C) Quantitative data of the percentage of IFN-γ+ cells within the CD8+ T-cell population. (D, E)The effect of different doses of GM-CSF encapsulated in hydrogelson DC-LV-OVA-based vaccine-specific T cell immune responses in vivo.Seven days after injection of hydrogels with different doses of GM-CSF,mice were immunized with DC-LV-OVA. A total of 14 days later, splenocyteswere collected, and OVA-specific CD8+ T cells were analyzedby intracellular staining for IFN-γ expression after stimulationwith OVA257–264 peptide for 6 h. The FACS data arerepresentative of four analyzed mice (D). Statistical data showingthe percentage of IFN-γ+ cells within the CD8+ T cell population (E).
© Copyright Policy - editor-choice
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4195289&req=5

fig3: Optimization of the two-step hybrid strategy to induceantigen-specificimmune responses. (A) Schematic representation showing immunizationprocedures. Mice were immunized with DC-LV-OVA at different time pointsafter GM-CSF hydrogel injection. (B) Flow cytometric analysis of IFN-γ+ cells within the CD8+ T-cell population in mousesplenocytes. (C) Quantitative data of the percentage of IFN-γ+ cells within the CD8+ T-cell population. (D, E)The effect of different doses of GM-CSF encapsulated in hydrogelson DC-LV-OVA-based vaccine-specific T cell immune responses in vivo.Seven days after injection of hydrogels with different doses of GM-CSF,mice were immunized with DC-LV-OVA. A total of 14 days later, splenocyteswere collected, and OVA-specific CD8+ T cells were analyzedby intracellular staining for IFN-γ expression after stimulationwith OVA257–264 peptide for 6 h. The FACS data arerepresentative of four analyzed mice (D). Statistical data showingthe percentage of IFN-γ+ cells within the CD8+ T cell population (E).
Mentions: The local recruitmentof immature DCs and macrophages by GM-CSFhydrogel allows for larger numbers of cells to be further modulatedwith antigen delivery vectors in situ. To test this hypothesis, previouslyreported SVGmu-pseudotyped lentiviral vectors encoding ovalbumin (OVA),22,28 which can target antigen delivery to DCs, were introduced to thesite of the hydrogel after DC recruitment. First, the optimal timegap between injection of GM-CSF hydrogel and immunization with vectorscarrying OVA (DC-LV-OVA) was determined (Figure 3A). Significantly more inflammatory cytokine interferon-γ (IFN-γ)was produced by CD8+ T cells from mice immunized by DC-LV-OVA7 days postinjection of GM-CSF hydrogel than at other times (Figure 3B,C), suggesting that this immunization schedulewas optimal for further study. The optimal dose of GM-CSF exposureto recruited DCs was also evaluated by measuring the degree of immuneresponses in mice injected with hydrogels encapsulating various amountsof GM-CSF. As shown in Figure 3D,E, the highestimmune response was found in mice injected with hydrogel encapsulating5 μg of GM-CSF. A higher concentration of GM-CSF (15 and 45μg) in hydrogel led to a decrease in IFN-γ production,suggesting that an optimal GM-CSF concentration is required to recruitand subsequently disperse the activated DCs to lymph nodes for immuneresponse induction.

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