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

Proc Natl Acad Sci U S A. 2002 Jul 9;99(14):9421-6. doi: 10.1073/pnas.132285699. Epub 2002 Jul 1.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antibodies, Neoplasm / metabolism*
  • Antibody Specificity
  • Antigen-Presenting Cells / immunology
  • Epitopes / genetics
  • Epitopes / metabolism
  • HLA-A2 Antigen / metabolism
  • Humans
  • Immunoglobulin Fab Fragments / genetics
  • Immunoglobulin Fab Fragments / metabolism
  • In Vitro Techniques
  • Melanoma / immunology
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism*
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Receptors, Antigen, T-Cell / metabolism
  • Recombinant Proteins / immunology
  • Recombinant Proteins / metabolism
  • Solubility
  • T-Lymphocytes / immunology*
  • gp100 Melanoma Antigen

Substances

  • Antibodies, Neoplasm
  • Epitopes
  • HLA-A2 Antigen
  • Immunoglobulin Fab Fragments
  • Membrane Glycoproteins
  • Neoplasm Proteins
  • PMEL protein, human
  • Receptors, Antigen, T-Cell
  • Recombinant Proteins
  • gp100 Melanoma Antigen