Direct visualization of distinct T cell epitopes derived from a melanoma tumor-associated antigen by using human recombinant antibodies with MHC- restricted T cell receptor-like specificity.
Specificity in the cellular immune system is controlled and regulated by the T cell antigen receptor (TCR), which specifically recognizes peptide/major histocompatibility complex (MHC) molecules. In recent years many cancer-associated MHC-restricted peptides have been isolated and because of their highly restricted fine specificity, they are desirable targets for novel approaches in immunotherapy. Antibodies that would recognize tumor-associated MHC-peptide complexes with the same specificity as the TCR would be valuable reagents for studying antigen presentation by tumor cells, for visualizing MHC-peptide complexes on cells, and eventually for monitoring the expression of specific complexes during immunotherapy. To generate molecules with such a unique fine specificity, we selected a large nonimmune repertoire of phage Fab antibodies on recombinant HLA-A2 complexed with three common antigenic T cell, HLA-A2-restricted epitopes derived from the melanoma differentiation antigen gp100. We were able to isolate a surprisingly large panel of human recombinant Fab antibodies that exhibit a characteristic TCR-like binding specificity to each of the three gp100-derived epitopes, yet unlike TCRs, they did so with an affinity in the nanomolar range. These TCR-like antibodies recognize the native MHC-peptide complex expressed on the surface of antigen-presenting cells. Moreover, they can detect the specific MHC-peptide complexes on the surface of melanoma tumor cells. These results demonstrate the ability to isolate high-affinity human recombinant antibodies with the antigen-specific, MHC-restricted specificity of T cells, and this ability was demonstrated for three different epitopes of the same melanoma-derived antigen.
Denkberg
Galit
G
Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Cohen
Cyril J
CJ
Lev
Avital
A
Chames
Patrick
P
Hoogenboom
Hennie R
HR
Reiter
Yoram
Y
D000595:Amino Acid Sequence; D000912:Antibodies, Neoplasm / Q000378:metabolism*; D000918:Antibody Specificity; D000938:Antigen-Presenting Cells / Q000276:immunology; D000939:Epitopes / Q000235:genetics / Q000378:metabolism; D015789:HLA-A2 Antigen / Q000378:metabolism; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000235:genetics / Q000378:metabolism; D066298:In Vitro Techniques; D008545:Melanoma / Q000276:immunology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D012995:Solubility; D013601:T-Lymphocytes / Q000276:immunology*; D058951:gp100 Melanoma Antigen
D000912:Antibodies, Neoplasm; D000939:Epitopes; D015789:HLA-A2 Antigen; D007140:Immunoglobulin Fab Fragments; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C548637:PMEL protein, human; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins; D058951:gp100 Melanoma Antigen