Antigenicity of human melanoma cells transfected to express the B7-1 co-stimulatory molecule (CD80) varies with the level of B7-1 expression.
The aim of this study was to compare the antigenicity of human melanoma cells molecularly modified by particle-mediated gene transfer to have transient or stable expression of the B7-1 co-stimulatory molecule (CD80). The unmodified melanoma cells (mel5, m21) had no constitutive expression of B7-1, but 22%-28% of cells had transient B7-1 expression 24 h following transfection with cDNA for B7-1 (mel5-B7, m21-B7). In addition, 85%-90% of cells had stable B7-1 expression following transfection with cDNA for B7-1 and in vitro culture under selection conditions (mel5-B7neo, m21-B7neo). Allogeneic HLA-unmatched normal donor peripheral blood mononuclear cells (PBMC) secreted greater amounts of granulocyte/macrophage-colony-stimulating factor (GM-CSF) when incubated for 3 days with m21-B7neo than did PBMC incubated with m21-B7, which, in turn, secreted greater amount of GM-CSF than PBMC incubated with m21. Similarly, cell-mediated cytotoxicity against unmodified melanoma cells by PBMC co-cultured for 5 days with the modified or unmodified melanoma cells was proportional to the level of B7-1 expression on the stimulating cells. This cytolytic activity had both an HLA-class-I-restricted and an HLA-class-I-unrestricted component. Following 5 days of co-culture, PBMC expression of CD28, the ligand for B7-1, was down-regulated in proportion to the level of B7-1 expression on the stimulating melanoma cells. Thus, particle-mediated gene delivery of cDNA for B7-1 into human melanoma cells increased expression of functional B7-1 and enhanced the antigenicity of the gene-modified cells in proportion to their level of B7-1 expression.
McCarthy
D O
DO
K4/414 Clinical Science Center, University of Wisconsin-Madison 53792, USA.
Glowacki
N
N
Schell
K
K
Emler
C A
CA
Albertini
M R
MR
D018122:B7-1 Antigen / Q000235:genetics / Q000502:physiology*; D016207:Cytokines / Q000096:biosynthesis; D003602:Cytotoxicity, Immunologic; D015234:HLA-A Antigens / Q000235:genetics; D006801:Humans; D016130:Immunophenotyping; D008213:Lymphocyte Activation; D008545:Melanoma / Q000276:immunology*; D014162:Transfection; D014407:Tumor Cells, Cultured
D018122:B7-1 Antigen; D016207:Cytokines; D015234:HLA-A Antigens