Recombinant antibodies with MHC‐restricted, peptide‐specific, T‐cell receptor‐like specificity: new tools to study antigen presentation and TCR–peptide–MHC interactions

Abstract

The advent in recent years of the application of tetrameric arrays of class I peptide-MHC complexes now enables us to detect and study rare populations of antigen-specific CD8+ T cells. However, available methods cannot visualize or determine the number and distribution of these TCR ligands on individual cells or detect antigen-presenting cells (APCs) in tissues. Here we describe a new approach that enables study of human class I peptide-MHC ligand-presentation as well as TCR-peptide-MHC interactions. Such studies are facilitated by applying novel tools in the form of peptide-specific, HLA-A2-restricted human recombinant antibodies directed toward a large variety of tumor-associated as well as viral T-cell epitope peptides. Using a large human antibody phage display library, a large panel of recombinant antibodies that are specific for a particular peptide-MHC class I complex in a peptide-dependent, MHC-restricted manner was isolated. These antibodies were used to directly visualize the specific MHC-peptide complex on tumor cells, antigen-presenting cells or virus-infected cells by flow cytometry. They enabled direct quantitation of the number of MHC-peptide complexes as well as in situ detection of the complex on the surface of APCs after naturally occurring active intracellular processing of the cognate antigen. These studies will enable also the development of a new class of targeting molecules to deliver drugs or toxins to tumor or virus-infected cells. Thus, we demonstrate our ability to transform the unique fine specificity but low intrinsic affinity of TCRs into high-affinity soluble antibody molecules endowed with a TCR-like specificity toward human tumor or viral epitopes. These molecules may prove to be crucial useful tools for studying MHC class I antigen presentation in health and disease as well as for therapeutic purposes in cancer, infectious diseases and autoimmune disorders.

Expression Hierarchy of T Cell Epitopes from Melanoma Differentiation Antigens: Unexpected High Level Presentation of Tyrosinase-HLA-A2 Complexes Revealed by Peptide-Specific, MHC-Restricted, TCR-Like Antibodies

“…Selection of phage Abs on biotinylated complexes was performed as described recently (21). Briefly, a large human Fab library containing 3.7 ϫ 10 10 different Fab clones was used for the selection.…”

Novel antibodies as anticancer agents

“…An alternative approach is the phage-display technology, which involves positive selection in the procedure (Hoogenboom et al, 1998). Using this approach, our laboratory has screened a very large human naı¨ve antibody library against a variety of recombinant human HLA-A2-peptide complexes displaying T-cell epitopes specific for antigens expressed in melanoma, prostate, breast, ovary and lung cancer (Cohen et al, 2002;Denkberg et al, 2002a;Denkberg et al, 2003;Cohen et al, 2003a;Held et al, 2004;Denkberg and Reiter, 2006).…”

Targeting TARP, a novel breast and prostate tumor‐associated antigen, with T cell receptor‐like human recombinant antibodies

“…These enabled us to screen these large libraries of such vast diversity and size in order to isolate these rare and unique TCR-like recombinant antibodies targeting human tumor and viral epitopes [21,22,[24][25][26].…”

“…Using antibody phage display approaches, we have recently generated such unique molecules, coined TCR-like antibodies, against a variety of tumor and viral epitopes restricted to human HLA-A2, the most frequent MHC allele in humans. These antibodies were utilized to detect, visualize and quantitate the number of specific tumor-and viral-associated HLA-A2/peptide complexes on tumor cells, APC, and virus-infected cells [21][22][23][24][25][26].…”

“…Using antibody phage display approaches, we have recently generated such unique molecules, coined TCR-like antibodies, against a variety of tumor and viral epitopes restricted to human HLA-A2, the most frequent MHC allele in humans. These antibodies were utilized to detect, visualize and quantitate the number of specific tumor-and viral-associated HLA-A2/peptide complexes on tumor cells, APC, and virus-infected cells [21][22][23][24][25][26].Another possible application of TCR-like antibodies is their use as targeting molecules to efficiently eliminate tumor cells due to the fact that they can mimic the unique fine specificity of T cells. This can be achieved by using the antibodies or their fragments as targeting moieties and arming them with effector modalities such as potent toxins, chemotherapeutic drugs, isotopes, or biological entities such as cytokines [27][28][29][30][31][32][33].…”