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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

Variation of CD4+, CD8+ cell populations in peripheral lymphoid organs Panel A, depicts the CD4/CD8+ and CD8/CD3+ ratios as analyzed by flow cytometry analysis from the Lymph node, LN (a, b) Panel B, depicts the CD4/CD8+ and CD8/CD3+ ratios as analyzed by flow cytometry analysis from the Spleen, SP (c, d), isolated from Tumor (control) and Treatment group mice at an interval of 3–4 d. *denotes p < 0.05,**denotes p < 0.01, ***denotes p < 0.001
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Fig3: Variation of CD4+, CD8+ cell populations in peripheral lymphoid organs Panel A, depicts the CD4/CD8+ and CD8/CD3+ ratios as analyzed by flow cytometry analysis from the Lymph node, LN (a, b) Panel B, depicts the CD4/CD8+ and CD8/CD3+ ratios as analyzed by flow cytometry analysis from the Spleen, SP (c, d), isolated from Tumor (control) and Treatment group mice at an interval of 3–4 d. *denotes p < 0.05,**denotes p < 0.01, ***denotes p < 0.001

Mentions: To further reveal variations of CD4+ and CD8+ T cells in the vaccinated and control mice, we stained the isolated CD3 + T cells from the draining LN and SP with specific anti-CD4 and -CD8 antibodies and examined their expression by FACS. The statistical results showed that the fluctuation of CD4/CD8 cell ratios during tumor progression after vaccination was significant and may reflect more rigorous and dynamic immune regulation and activity in the Treatment group (Fig. 3Aa and Bc). Moreover, ratios of CD8/CD3 cells in Treatment group was higher than the Tumor group in all time points in LN and in time points d-7 to d + 13 in SP (Fig. 3Ab and Bd). Then we found that the mice from the Treatment group were not able to form tumors when they were re-inoculated with the tumor cells (data not shown). The results indicated that T cell immune memory formed after vaccination protecting against tumor attacks. Furthermore, we detected the ability of the tumor-specific T cells.Fig. 3


An effective cytokine adjuvant vaccine induces autologous T-cell response against colon cancer in an animal model
Variation of CD4+, CD8+ cell populations in peripheral lymphoid organs Panel A, depicts the CD4/CD8+ and CD8/CD3+ ratios as analyzed by flow cytometry analysis from the Lymph node, LN (a, b) Panel B, depicts the CD4/CD8+ and CD8/CD3+ ratios as analyzed by flow cytometry analysis from the Spleen, SP (c, d), isolated from Tumor (control) and Treatment group mice at an interval of 3–4 d. *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

Fig3: Variation of CD4+, CD8+ cell populations in peripheral lymphoid organs Panel A, depicts the CD4/CD8+ and CD8/CD3+ ratios as analyzed by flow cytometry analysis from the Lymph node, LN (a, b) Panel B, depicts the CD4/CD8+ and CD8/CD3+ ratios as analyzed by flow cytometry analysis from the Spleen, SP (c, d), isolated from Tumor (control) and Treatment group mice at an interval of 3–4 d. *denotes p < 0.05,**denotes p < 0.01, ***denotes p < 0.001
Mentions: To further reveal variations of CD4+ and CD8+ T cells in the vaccinated and control mice, we stained the isolated CD3 + T cells from the draining LN and SP with specific anti-CD4 and -CD8 antibodies and examined their expression by FACS. The statistical results showed that the fluctuation of CD4/CD8 cell ratios during tumor progression after vaccination was significant and may reflect more rigorous and dynamic immune regulation and activity in the Treatment group (Fig. 3Aa and Bc). Moreover, ratios of CD8/CD3 cells in Treatment group was higher than the Tumor group in all time points in LN and in time points d-7 to d + 13 in SP (Fig. 3Ab and Bd). Then we found that the mice from the Treatment group were not able to form tumors when they were re-inoculated with the tumor cells (data not shown). The results indicated that T cell immune memory formed after vaccination protecting against tumor attacks. Furthermore, we detected the ability of the tumor-specific T cells.Fig. 3

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