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Tumor cell secretion of soluble factor(s) for specific immunosuppression.

Kano A - Sci Rep (2015)

Bottom Line: This reduction may be due to the relatively decreased lymphocytes and increased granulocytes in a spleen accompanied by splenomegaly with time after the 4T1 inoculation.These results suggest that the IFN-γ suppression is 4T1 tumor-specific.The cytokine tip assay demonstrated several known cytokines that negatively regulate immune responses and may be candidates for this immunosuppression activity.

View Article: PubMed Central - PubMed

Affiliation: Institute for Materials Chemistry and Engineering, Kyushu University.

ABSTRACT
Studies of tumor models using syngeneic transplantation have advanced our understanding of tumor immunity, including both immune surveillance and evasion. Murine mammary carcinoma 4T1 cells secrete immunosuppressive soluble factors as demonstrated in splenocyte culture. Cultured primary splenocytes secrete IFN-γ, which was strikingly elevated when the cells were isolated from 4T1 tumor-bearing mice. The secretion of IFN-γ peaked a week after 4T1 inoculation and then declined. This reduction may be due to the relatively decreased lymphocytes and increased granulocytes in a spleen accompanied by splenomegaly with time after the 4T1 inoculation. IFN-γ production was further suppressed with the addition of the conditioned media from 4T1 cells to the splenocyte culture. This suppressive effect was more evident in the splenocytes isolated from mice that had 4T1 tumors for a longer period of time and was not observed in the conditioned medium either from CT26 cells or with splenocytes isolated from CT26 tumor-bearing mice. These results suggest that the IFN-γ suppression is 4T1 tumor-specific. The soluble factor(s) in the 4T1-conditioned media was a protein between 10 to 100 kDa. The cytokine tip assay demonstrated several known cytokines that negatively regulate immune responses and may be candidates for this immunosuppression activity.

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Quantitative RT-PCR in cultured splenocytes isolated from 4T1 tumor-bearing mice.The fold changes in mRNA expression of IFN-γ, Thy1, and F4/80 with or without 4T1-conditioned medium (4T1CM) compared with the initial levels (3 h culture) are shown. The quantitative RT-PCR was performed in triplicate and the results were expressed as mean ± SD. The splenocytes were isolated from three mice and typical results are shown.
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f3: Quantitative RT-PCR in cultured splenocytes isolated from 4T1 tumor-bearing mice.The fold changes in mRNA expression of IFN-γ, Thy1, and F4/80 with or without 4T1-conditioned medium (4T1CM) compared with the initial levels (3 h culture) are shown. The quantitative RT-PCR was performed in triplicate and the results were expressed as mean ± SD. The splenocytes were isolated from three mice and typical results are shown.

Mentions: The quantitative RT-PCR was performed in the cultured splenocytes isolated from the mouse bearing 4T1 tumor for three weeks (Fig. 3). The IFN-γ expression was upregulated several folds in 24 h and more than 20-fold in 48 h compared to the 3 h-cultured splenocytes, while it was suppressed substantially in 48 h culture with the 4T1-conditioned medium. The Thy1 expression, a T cell marker, was slightly reduced, however, there was no difference between 24 h and 48 h. Therefore it is unlikely that the reduction of T cell number is the reason for the IFN-γ suppression by 4T1-conditioned media. On the other hand, the expression of F4/80 was increased in 48 h culture with 4T1-conditioned media, suggesting monocyte proliferation. Taken together, these results suggest that the IFN-γ expression in splenocytes is upregulated in the mRNA level and this upregulation is suppressed by 4T1-conditioned media. The proliferated monocytes may inhibit the T cell activation.


Tumor cell secretion of soluble factor(s) for specific immunosuppression.

Kano A - Sci Rep (2015)

Quantitative RT-PCR in cultured splenocytes isolated from 4T1 tumor-bearing mice.The fold changes in mRNA expression of IFN-γ, Thy1, and F4/80 with or without 4T1-conditioned medium (4T1CM) compared with the initial levels (3 h culture) are shown. The quantitative RT-PCR was performed in triplicate and the results were expressed as mean ± SD. The splenocytes were isolated from three mice and typical results are shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4352862&req=5

f3: Quantitative RT-PCR in cultured splenocytes isolated from 4T1 tumor-bearing mice.The fold changes in mRNA expression of IFN-γ, Thy1, and F4/80 with or without 4T1-conditioned medium (4T1CM) compared with the initial levels (3 h culture) are shown. The quantitative RT-PCR was performed in triplicate and the results were expressed as mean ± SD. The splenocytes were isolated from three mice and typical results are shown.
Mentions: The quantitative RT-PCR was performed in the cultured splenocytes isolated from the mouse bearing 4T1 tumor for three weeks (Fig. 3). The IFN-γ expression was upregulated several folds in 24 h and more than 20-fold in 48 h compared to the 3 h-cultured splenocytes, while it was suppressed substantially in 48 h culture with the 4T1-conditioned medium. The Thy1 expression, a T cell marker, was slightly reduced, however, there was no difference between 24 h and 48 h. Therefore it is unlikely that the reduction of T cell number is the reason for the IFN-γ suppression by 4T1-conditioned media. On the other hand, the expression of F4/80 was increased in 48 h culture with 4T1-conditioned media, suggesting monocyte proliferation. Taken together, these results suggest that the IFN-γ expression in splenocytes is upregulated in the mRNA level and this upregulation is suppressed by 4T1-conditioned media. The proliferated monocytes may inhibit the T cell activation.

Bottom Line: This reduction may be due to the relatively decreased lymphocytes and increased granulocytes in a spleen accompanied by splenomegaly with time after the 4T1 inoculation.These results suggest that the IFN-γ suppression is 4T1 tumor-specific.The cytokine tip assay demonstrated several known cytokines that negatively regulate immune responses and may be candidates for this immunosuppression activity.

View Article: PubMed Central - PubMed

Affiliation: Institute for Materials Chemistry and Engineering, Kyushu University.

ABSTRACT
Studies of tumor models using syngeneic transplantation have advanced our understanding of tumor immunity, including both immune surveillance and evasion. Murine mammary carcinoma 4T1 cells secrete immunosuppressive soluble factors as demonstrated in splenocyte culture. Cultured primary splenocytes secrete IFN-γ, which was strikingly elevated when the cells were isolated from 4T1 tumor-bearing mice. The secretion of IFN-γ peaked a week after 4T1 inoculation and then declined. This reduction may be due to the relatively decreased lymphocytes and increased granulocytes in a spleen accompanied by splenomegaly with time after the 4T1 inoculation. IFN-γ production was further suppressed with the addition of the conditioned media from 4T1 cells to the splenocyte culture. This suppressive effect was more evident in the splenocytes isolated from mice that had 4T1 tumors for a longer period of time and was not observed in the conditioned medium either from CT26 cells or with splenocytes isolated from CT26 tumor-bearing mice. These results suggest that the IFN-γ suppression is 4T1 tumor-specific. The soluble factor(s) in the 4T1-conditioned media was a protein between 10 to 100 kDa. The cytokine tip assay demonstrated several known cytokines that negatively regulate immune responses and may be candidates for this immunosuppression activity.

Show MeSH
Related in: MedlinePlus