Inefficient presentation of tumor-derived antigen by tumor-infiltrating dendritic cells.
BACKGROUND
Transplantable B16 melanoma is widely used as a tumor model to investigate tumor immunity. We wished to characterize the leukocyte populations infiltrating B16 melanoma tumors, and the functional properties of tumor-infiltrating dendritic cells (TIDC).


METHODS
We used the B16 melanoma cell line expressing ovalbumin protein (OVA) to investigate the phenotype and T cell stimulatory capacity of TIDC.


RESULTS
The majority of leukocytes in B16 melanoma were macrophages, which colocalized with TIDCs, B and T cells to the peripheral area of the tumor. Both myeloid and plasmacytoid DC populations were present within tumors. Most of these DCs appeared immature, but about a third expressed a mature phenotype. TIDCs did not present tumor-derived antigen, as they were unable to induce the proliferation of tumor-specific CD4+ and CD8+ T cells in vitro unless in the presence of specific peptides. Some presentation of tumor-derived antigen could be demonstrated in the tumor-draining lymph node using in vivo proliferation assays. However, while proliferation of CD8+ T cells was reproducibly demonstrated, no proliferation of CD4+ T cells was observed.


CONCLUSIONS
In summary, our data suggest that DCs in tumors have limited antigen-presenting function. Inefficient antigen presentation extends to the tumor-draining lymph node, and may affect the generation of antitumor immune responses.
Stoitzner
Patrizia
P
Malaghan Institute of Medical Research, Wellington, New Zealand. Patrizia.Stoitzner@i-med.ac.at
Green
Laura K
LK
Jung
Jae Y
JY
Price
Kylie M
KM
Atarea
Haley
H
Kivell
Bronwyn
B
Ronchese
Franca
F
D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D000938:Antigen-Presenting Cells / Q000276:immunology / Q000473:pathology; D000951:Antigens, Neoplasm / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000473:pathology; D049109:Cell Proliferation; D003713:Dendritic Cells / Q000276:immunology* / Q000473:pathology; D005260:Female; D007962:Leukocytes / Q000276:immunology / Q000473:pathology; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D008297:Male; D008546:Melanoma, Experimental / Q000276:immunology* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000276:immunology*; D010641:Phenotype; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000473:pathology
D000951:Antigens, Neoplasm; D010047:Ovalbumin