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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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Characterization of the immunosuppressive activity in 4T1-conditioned medium.(A). Splenocytes isolated from a 4T1 tumor-bearing mouse were cultured with 4T1-conditioned medium fractionated with the indicated ultrafiltration, and IFN-γ in the culture medium was measured. (B). TGF-β in 4T1-conditioned medium cultured for the indicated days was measured. The samples were treated with or without acid. Splenocyte culture was performed in triplicate and the results were expressed as mean ± SD. Typical results are shown.
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f5: Characterization of the immunosuppressive activity in 4T1-conditioned medium.(A). Splenocytes isolated from a 4T1 tumor-bearing mouse were cultured with 4T1-conditioned medium fractionated with the indicated ultrafiltration, and IFN-γ in the culture medium was measured. (B). TGF-β in 4T1-conditioned medium cultured for the indicated days was measured. The samples were treated with or without acid. Splenocyte culture was performed in triplicate and the results were expressed as mean ± SD. Typical results are shown.

Mentions: It was expected that the soluble factors in the conditioned medium played a key role in the observed reduction in IFN-γ secretion by splenocytes. At first, ultrafiltered fractions of the 4T1-conditioned medium were tested (Fig. 5A). The suppressive activity of the conditioned medium with 10% serum were observed in the fraction that passed through the 300 kDa and did not pass through the 100 kDa molecular weight cut-off (MWCO) filters. The activity of the medium without serum was observed in the fractions that passed through both the 300 kDa and 100 kDa filters (Fig. 5A) but not through the 10 kDa filters (data not shown). These results suggest that the immune suppressive soluble factor(s) is between 10 to 100 kDa molecular weight and are bound to serum proteins. Combined with the finding that the activity was heat-sensitive (data not shown), the factor(s) was predicted to be a protein.


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

Kano A - Sci Rep (2015)

Characterization of the immunosuppressive activity in 4T1-conditioned medium.(A). Splenocytes isolated from a 4T1 tumor-bearing mouse were cultured with 4T1-conditioned medium fractionated with the indicated ultrafiltration, and IFN-γ in the culture medium was measured. (B). TGF-β in 4T1-conditioned medium cultured for the indicated days was measured. The samples were treated with or without acid. Splenocyte culture was performed in triplicate and the results were expressed as mean ± SD. Typical results are shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: Characterization of the immunosuppressive activity in 4T1-conditioned medium.(A). Splenocytes isolated from a 4T1 tumor-bearing mouse were cultured with 4T1-conditioned medium fractionated with the indicated ultrafiltration, and IFN-γ in the culture medium was measured. (B). TGF-β in 4T1-conditioned medium cultured for the indicated days was measured. The samples were treated with or without acid. Splenocyte culture was performed in triplicate and the results were expressed as mean ± SD. Typical results are shown.
Mentions: It was expected that the soluble factors in the conditioned medium played a key role in the observed reduction in IFN-γ secretion by splenocytes. At first, ultrafiltered fractions of the 4T1-conditioned medium were tested (Fig. 5A). The suppressive activity of the conditioned medium with 10% serum were observed in the fraction that passed through the 300 kDa and did not pass through the 100 kDa molecular weight cut-off (MWCO) filters. The activity of the medium without serum was observed in the fractions that passed through both the 300 kDa and 100 kDa filters (Fig. 5A) but not through the 10 kDa filters (data not shown). These results suggest that the immune suppressive soluble factor(s) is between 10 to 100 kDa molecular weight and are bound to serum proteins. Combined with the finding that the activity was heat-sensitive (data not shown), the factor(s) was predicted to be a protein.

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