Whole lymphoma B cells allow efficient cross-presentation of antigens by dendritic cells.
BACKGROUND
In order to compensate for the paucity of defined tumor antigens (Ag) in non-Hodgkin's lymphomas, a promising approach might be the use of whole tumor cells as a source of tumor Ag to pulse antigen-presenting cells (APC). However, it is not presently known how the tumor cells should be delivered to APC to optimize the cross-presentation of tumor Ag to anti-tumor CD8 T cells. We aimed to compare CD20-opsonized, apoptotic and necrotic human tumor cells for their capacity to induce endocytosis and cross-presentation of tumor-associated Ag by dendritic cells (DC) or macrophages.


METHODS
Endocytosis of human tumor-derived material by macrophages or DC was monitored by flow cytometry. We used a previously described influenza model and studied cross-presentation of viral Ag as cellular surrogate tumor-associated Ag by APC after endocytosis of lymphoma B cells treated by inactivated influenza virus.


RESULTS
Optimal endocytosis was obtained when tumor cells were opsonized by an anti-CD20 antibody and, as expected, macrophages were more phagocytic than DC. However, Ag from opsonized, apoptotic and live cells, but not from necrotic lymphoma cells, were efficiently cross-presented by DC but not by macrophages.


CONCLUSIONS
We have developed a new model with human primary lymphoma cells to study the cross-presentation of tumor-associated Ag by APC. The results we have obtained support the use of whole lymphoma cells from patients to pulse DC to induce an anti-tumor immune response.
Manches
O
O
EFS Rhone-Alpes, Laboratoire R&D, La Tronche, France.
Lui
G
G
Molens
J P
JP
Sotto
J J
JJ
Chaperot
L
L
Plumas
J
J
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D058846:Antibodies, Monoclonal, Murine-Derived; D017951:Antigen Presentation / Q000187:drug effects / Q000276:immunology; D018951:Antigens, CD20 / Q000276:immunology; D000951:Antigens, Neoplasm / Q000187:drug effects / Q000276:immunology; D000956:Antigens, Viral / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D045142:Cross-Priming / Q000276:immunology*; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000821:virology; D006801:Humans; D007155:Immunologic Factors / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000276:immunology; D016393:Lymphoma, B-Cell / Q000276:immunology*; D008264:Macrophages / Q000166:cytology / Q000276:immunology*; D009975:Orthomyxoviridae / Q000276:immunology; D000069283:Rituximab
D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D018951:Antigens, CD20; D000951:Antigens, Neoplasm; D000956:Antigens, Viral; D007155:Immunologic Factors; D000069283:Rituximab