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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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Suppression of IFN-γ secretion by splenocytes isolated from 4T1 tumor-bearing mice.(A). Splenocytes isolated on the indicated day after 4T1 inoculation were cultured with 4T1 cells, and IFN-γ and TNF-α in the culture medium were measured. Splenocyte culture was performed in triplicate and the results were expressed as mean ± SD. The data are expressed as the percentage of the findings with splenocytes alone. Typical results are shown. (B). Splenocytes isolated on the indicated day after 4T1 cell inoculation were cultured with the conditioned medium of 4T1 cells, and IFN-γ and TNF-α in the culture medium were measured. The data are expressed as the percentage of the findings without the conditioned medium. The splenocytes were isolated from three mice each, and the average is shown. The errors quoted are standard deviation from the mean. NS: No significance.
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f2: Suppression of IFN-γ secretion by splenocytes isolated from 4T1 tumor-bearing mice.(A). Splenocytes isolated on the indicated day after 4T1 inoculation were cultured with 4T1 cells, and IFN-γ and TNF-α in the culture medium were measured. Splenocyte culture was performed in triplicate and the results were expressed as mean ± SD. The data are expressed as the percentage of the findings with splenocytes alone. Typical results are shown. (B). Splenocytes isolated on the indicated day after 4T1 cell inoculation were cultured with the conditioned medium of 4T1 cells, and IFN-γ and TNF-α in the culture medium were measured. The data are expressed as the percentage of the findings without the conditioned medium. The splenocytes were isolated from three mice each, and the average is shown. The errors quoted are standard deviation from the mean. NS: No significance.

Mentions: To investigate the activation of T cells that would target 4T1 cells, the splenocytes isolated from a 4T1 tumor-bearing mouse at the indicated day after tumor inoculation were cultured with 4T1 cells (Fig. 2A). Unexpectedly, the secretion of IFN-γ was suppressed by co-culture with 4T1 cells and this reduction was more notable in the splenocytes that were isolated from mice bearing 4T1 tumors for a longer time as compared to those mice carrying the tumors for shorter periods of time. In contrast, co-culture had no effect on TNF-α levels whether the splenocytes were from tumor-bearing mice or not. Next, the conditioned medium of 4T1 cells was used for splenocyte culture, and IFN-γ levels were examined. The secretion of IFN-γ was suppressed by the 10% conditioned medium, and the level of this suppression was also dependent on the length of time the mice had the tumors (Fig. 2B). The conditioned medium from 4T1 cells did not affect the levels of TNF-α secreted from any of the splenocytes.


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

Kano A - Sci Rep (2015)

Suppression of IFN-γ secretion by splenocytes isolated from 4T1 tumor-bearing mice.(A). Splenocytes isolated on the indicated day after 4T1 inoculation were cultured with 4T1 cells, and IFN-γ and TNF-α in the culture medium were measured. Splenocyte culture was performed in triplicate and the results were expressed as mean ± SD. The data are expressed as the percentage of the findings with splenocytes alone. Typical results are shown. (B). Splenocytes isolated on the indicated day after 4T1 cell inoculation were cultured with the conditioned medium of 4T1 cells, and IFN-γ and TNF-α in the culture medium were measured. The data are expressed as the percentage of the findings without the conditioned medium. The splenocytes were isolated from three mice each, and the average is shown. The errors quoted are standard deviation from the mean. NS: No significance.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Suppression of IFN-γ secretion by splenocytes isolated from 4T1 tumor-bearing mice.(A). Splenocytes isolated on the indicated day after 4T1 inoculation were cultured with 4T1 cells, and IFN-γ and TNF-α in the culture medium were measured. Splenocyte culture was performed in triplicate and the results were expressed as mean ± SD. The data are expressed as the percentage of the findings with splenocytes alone. Typical results are shown. (B). Splenocytes isolated on the indicated day after 4T1 cell inoculation were cultured with the conditioned medium of 4T1 cells, and IFN-γ and TNF-α in the culture medium were measured. The data are expressed as the percentage of the findings without the conditioned medium. The splenocytes were isolated from three mice each, and the average is shown. The errors quoted are standard deviation from the mean. NS: No significance.
Mentions: To investigate the activation of T cells that would target 4T1 cells, the splenocytes isolated from a 4T1 tumor-bearing mouse at the indicated day after tumor inoculation were cultured with 4T1 cells (Fig. 2A). Unexpectedly, the secretion of IFN-γ was suppressed by co-culture with 4T1 cells and this reduction was more notable in the splenocytes that were isolated from mice bearing 4T1 tumors for a longer time as compared to those mice carrying the tumors for shorter periods of time. In contrast, co-culture had no effect on TNF-α levels whether the splenocytes were from tumor-bearing mice or not. Next, the conditioned medium of 4T1 cells was used for splenocyte culture, and IFN-γ levels were examined. The secretion of IFN-γ was suppressed by the 10% conditioned medium, and the level of this suppression was also dependent on the length of time the mice had the tumors (Fig. 2B). The conditioned medium from 4T1 cells did not affect the levels of TNF-α secreted from any of the splenocytes.

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