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An effective cytokine adjuvant vaccine induces autologous T-cell response against colon cancer in an animal model

View Article: PubMed Central - PubMed

ABSTRACT

Background: Despite recent advances in early detection and improvements in chemotherapy for colon cancer, the patients still face poor prognosis of postoperative recurrence and metastasis, the median survival for patients with metastatic colorectal cancer is approximately 22–24 months. Some immunotherapeutic approaches had been attempted in colon cancer patients to significantly increase overall survival. A vaccine based approach has shown a novel direction for colon cancer prevention and therapy.

Methods: In this study, the experiments were designed including prevention and therapeutic stages in order to attain effect against tumor recurrence in clinical settings. The anti-tumor efficacy of a novel cytokine adjuvant vaccine that contained cytokines GM-CSF and IL-2 and inactivated colon CT26.WT whole cell antigen was evaluated in BALB/c mouse tumor models by measuring tumor growth post vaccination and the survival time of tumor-bearing mice, analyzing the expression and distribution of CD4, CD8, CD11c, CD80, CD86 and CD83 positive cells in control and treated mice by flow cytometry and immunochemistry. The tumor-specific cytotoxic T cells (CTL) were analyzed by tumor proliferation and the lactic dehydrogenates (LDH) release assays. IFN-γ, IL-2 and GM-CSF secretion in serum was assayed by ELISA.

Results: Our results suggested that cytokine adjuvant vaccine significantly inhibited tumor growth and extended the survival period at least 160d. It was found that the levels of CD8 + T and the tumor-specific cytotoxicity were significantly higher in prevention and treatment group vaccinated by cytokine adjuvant vaccine. CD8 + T cells play a key role in anti-tumor response.

Conclusions: The novel GM-CSF and IL-2 based adjuvant vaccine effectively activated autologous T-cell response and represented a promising immunotherapeutic approach for patients with colon cancer.

Electronic supplementary material: The online version of this article (doi:10.1186/s12865-016-0172-x) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus

Tumor specific CTL activity in peripheral lymphoid organs and cytokines secretion in the serum The peripheral immune organs (LN and SP) were collected (3 mice/per group), and CD3+ T cells were isolated. These cells were incubated with CT26.WT tumor cells. Panel (a), represent the LDH release induced by T cells isolated from LN (left) and SP (right) of tumor control or treatment group mice. Panel (b), represents the CT26.WT tumor cell proliferation as measured by MTT assay post incubation with effector T cells at an E: T ration of 50:1. Panel (c), represents the secretion of cytokines measured by ELISA kit from the serum of tumor control and treatment group mice. Data are represented as mean ± SD. *denotes p < 0.05,**denotes p < 0.01, ***denotes p < 0.001
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Fig4: Tumor specific CTL activity in peripheral lymphoid organs and cytokines secretion in the serum The peripheral immune organs (LN and SP) were collected (3 mice/per group), and CD3+ T cells were isolated. These cells were incubated with CT26.WT tumor cells. Panel (a), represent the LDH release induced by T cells isolated from LN (left) and SP (right) of tumor control or treatment group mice. Panel (b), represents the CT26.WT tumor cell proliferation as measured by MTT assay post incubation with effector T cells at an E: T ration of 50:1. Panel (c), represents the secretion of cytokines measured by ELISA kit from the serum of tumor control and treatment group mice. Data are represented as mean ± SD. *denotes p < 0.05,**denotes p < 0.01, ***denotes p < 0.001

Mentions: We further analyzed whether such a cytokine adjuvant vaccination enhanced tumor-specific CTL response. LDH assay was performed to analyze the cytotoxic effect. The results demonstrated that CD8 + T cells isolated from draining lymph nodes and the spleen of the vaccinated mice resulted in induction of higher LDH release by CT26.WT tumor cells in all time points in the Treatment group (Fig. 4a). In addition, the CTL activity was also examined by analyzing the target cell proliferation. The results showed that CT26.WT tumor cell proliferation was significantly reduced in samples that had CD8 + T cells from LN and SP of Treatment groups, at all time points as observed in Fig. 4b. These data suggested that CD8 + T cells isolated from the vaccinated mice were more effective in generating CTL response. Next, we analyzed the levels of cytokines IFN-γ, IL-2 and GM-CSF most probably produced by activated T cells in serum. The data from different time points suggested that, the Treatment group had significantly periodic increases in the IFN-γ and IL-2 levels as compared to the tumor group (Fig. 4c). Both cytokine levels peaked 2 d and 6 d post tumor cell inoculation and were significant higher in the vaccinated mice (p < 0.05). The levels of GM-CSF in serum in Treatment group were higher than the Tumor group which may stand for immune status for presenting antigen (Additional file 2: Figure S2). Collectively, this data suggested that the autolougous T-cell response were effectively elicited and significantly stronger in the Treatment group.Fig. 4


An effective cytokine adjuvant vaccine induces autologous T-cell response against colon cancer in an animal model
Tumor specific CTL activity in peripheral lymphoid organs and cytokines secretion in the serum The peripheral immune organs (LN and SP) were collected (3 mice/per group), and CD3+ T cells were isolated. These cells were incubated with CT26.WT tumor cells. Panel (a), represent the LDH release induced by T cells isolated from LN (left) and SP (right) of tumor control or treatment group mice. Panel (b), represents the CT26.WT tumor cell proliferation as measured by MTT assay post incubation with effector T cells at an E: T ration of 50:1. Panel (c), represents the secretion of cytokines measured by ELISA kit from the serum of tumor control and treatment group mice. Data are represented as mean ± SD. *denotes p < 0.05,**denotes p < 0.01, ***denotes p < 0.001
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5037582&req=5

Fig4: Tumor specific CTL activity in peripheral lymphoid organs and cytokines secretion in the serum The peripheral immune organs (LN and SP) were collected (3 mice/per group), and CD3+ T cells were isolated. These cells were incubated with CT26.WT tumor cells. Panel (a), represent the LDH release induced by T cells isolated from LN (left) and SP (right) of tumor control or treatment group mice. Panel (b), represents the CT26.WT tumor cell proliferation as measured by MTT assay post incubation with effector T cells at an E: T ration of 50:1. Panel (c), represents the secretion of cytokines measured by ELISA kit from the serum of tumor control and treatment group mice. Data are represented as mean ± SD. *denotes p < 0.05,**denotes p < 0.01, ***denotes p < 0.001
Mentions: We further analyzed whether such a cytokine adjuvant vaccination enhanced tumor-specific CTL response. LDH assay was performed to analyze the cytotoxic effect. The results demonstrated that CD8 + T cells isolated from draining lymph nodes and the spleen of the vaccinated mice resulted in induction of higher LDH release by CT26.WT tumor cells in all time points in the Treatment group (Fig. 4a). In addition, the CTL activity was also examined by analyzing the target cell proliferation. The results showed that CT26.WT tumor cell proliferation was significantly reduced in samples that had CD8 + T cells from LN and SP of Treatment groups, at all time points as observed in Fig. 4b. These data suggested that CD8 + T cells isolated from the vaccinated mice were more effective in generating CTL response. Next, we analyzed the levels of cytokines IFN-γ, IL-2 and GM-CSF most probably produced by activated T cells in serum. The data from different time points suggested that, the Treatment group had significantly periodic increases in the IFN-γ and IL-2 levels as compared to the tumor group (Fig. 4c). Both cytokine levels peaked 2 d and 6 d post tumor cell inoculation and were significant higher in the vaccinated mice (p < 0.05). The levels of GM-CSF in serum in Treatment group were higher than the Tumor group which may stand for immune status for presenting antigen (Additional file 2: Figure S2). Collectively, this data suggested that the autolougous T-cell response were effectively elicited and significantly stronger in the Treatment group.Fig. 4

View Article: PubMed Central - PubMed

ABSTRACT

Background: Despite recent advances in early detection and improvements in chemotherapy for colon cancer, the patients still face poor prognosis of postoperative recurrence and metastasis, the median survival for patients with metastatic colorectal cancer is approximately 22&ndash;24 months. Some immunotherapeutic approaches had been attempted in colon cancer patients to significantly increase overall survival. A vaccine based approach has shown a novel direction for colon cancer prevention and therapy.

Methods: In this study, the experiments were designed including prevention and therapeutic stages in order to attain effect against tumor recurrence in clinical settings. The anti-tumor efficacy of a novel cytokine adjuvant vaccine that contained cytokines GM-CSF and IL-2 and inactivated colon CT26.WT whole cell antigen was evaluated in BALB/c mouse tumor models by measuring tumor growth post vaccination and the survival time of tumor-bearing mice, analyzing the expression and distribution of CD4, CD8, CD11c, CD80, CD86 and CD83 positive cells in control and treated mice by flow cytometry and immunochemistry. The tumor-specific cytotoxic T cells (CTL) were analyzed by tumor proliferation and the lactic dehydrogenates (LDH) release assays. IFN-&gamma;, IL-2 and GM-CSF secretion in serum was assayed by ELISA.

Results: Our results suggested that cytokine adjuvant vaccine significantly inhibited tumor growth and extended the survival period at least 160d. It was found that the levels of CD8&thinsp;+&thinsp;T and the tumor-specific cytotoxicity were significantly higher in prevention and treatment group vaccinated by cytokine adjuvant vaccine. CD8&thinsp;+&thinsp;T cells play a key role in anti-tumor response.

Conclusions: The novel GM-CSF and IL-2 based adjuvant vaccine effectively activated autologous T-cell response and represented a promising immunotherapeutic approach for patients with colon cancer.

Electronic supplementary material: The online version of this article (doi:10.1186/s12865-016-0172-x) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus