Characterization of an HLA-restricted and human cytomegalovirus-specific antibody repertoire with therapeutic potential

Moritz Bewarder,Dominic Kaddu-Mulindwa,Niels Murawski,Arne Felbel,Birgit Bette,Alexander Hasse,Konstantinos Christofyllakis,Klaus-Dieter Preuss,Joerg Thomas Bittenbring,Frank Neumann,Gerhard Held,Stephan Stilgenbauer,Lorenz Thurner,Gabi Carbon,Sigrun Smola

doi:10.1007/s00262-020-02564-1

Moritz Bewarder, Dominic Kaddu-Mulindwa + Show 13 more

Open Access

https://doi.org/10.1007/s00262-020-02564-1

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Abstract

With an infection rate of 60–90%, the human cytomegalovirus (HCMV) is very common among adults but normally causes no symptoms. When T cell-mediated immunity is compromised, HCMV reactivation can lead to increased morbidity and mortality. HCMV antigens are processed and presented as peptides on the cell surface via HLA I complexes to the T cell receptor (TCR) of T cells. The generation of antibodies against HCMV peptides presented on HLA complexes (TCR-like antibodies) has been described, but is without therapeutic applications to date due to the polygenic and polymorphic nature of HLA genes. We set out to obtain antibodies specific for HLA/HCMV-peptides, covering the majority of HLA alleles present in European populations. Using phage display technology, we selected 10 Fabs, able to bind to HCMV-peptides presented in the 6 different HLA class I alleles A*0101, A*0201, A*2402, B*0702, B*0801 and B*3501. We demonstrate specific binding of all selected Fabs to HLA-typed lymphoblastoid cell lines (EBV-transformed B cells) and lymphocytes loaded with HCMV-peptides. After infection with HCMV, 4/10 tetramerized Fabs restricted to the alleles HLA-A*0101, HLA-A*0201 and HLA-B*0702 showed binding to infected primary fibroblasts. When linked to the pseudomonas exotoxin A, these Fab antibodies induce highly specific cytotoxicity in HLA matched cell lines loaded with HCMV peptides. TCR-like antibody repertoires therefore represent a promising new treatment modality for viral infections and may also have applications in the treatment of cancers.

Highlights

human cytomegalovirus (HCMV) is a double-stranded DNA virus and member of the Herpesviridae family
We found that T cell responses with specificity for 6 HCMV-derived peptides presented on 6/7 of these most prevalent human leukocyte antigen I (HLA I) complexes, have previously been described [35,36,37,38]
Five of six peptides that induce T cell responses derive from the immunodominant HCMV-antigen pp65 and one peptide derives from IE1 (Table 1)

Summary

Introduction

HCMV persists after acute infection and establishes latent infection in a non- or slowly replicating form. Infection with HCMV is very common among adults (60–90%) and primary infection often does not cause any symptoms. In rare cases primary infection can cause HCMV mononucleosis with fever, lymphadenopathy and relative lymphocytosis. After allogeneic hematopoietic stem cell transplantation (HSCT) or solid organ transplantation, T cell-mediated immunity is often suppressed and HCMV reactivation can significantly contribute to morbidity and mortality after transplantation [3, 4]. HCMV is one of the most common opportunistic pathogens detected after HSCT or solid organ transplantation and can cause severe pneumonia, hepatitis, encephalitis, colitis or ulcers of the gastrointestinal tract [3, 4]. Patients undergoing transplantation and patients with HIV-induced immunodeficiency suffer from HCMVrelated diseases like retinitis and polyradiculopathy [5, 6]

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