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Abstract Number: 123

Blockade of Antigen-specific T Cell Activation by a Non-Depleting Anti-HLA-DR Monoclonal Antibody with a Unique Binding Epitope

Fang Shen1, Karen Duffy 1, Stephane Becart 2, Robert Kuhn 1, Melissa Swiecki 1, Brian Jones 1, Yawei Li 1, Jeffrey Hall 1, Ravi Malaviya 1, Nathan Felix 1, Mimi Zhou 2, Sunil Nagpal 1 and Navin Rao 1, 1Janssen R&D, Spring House, PA, 2Janssen R&D, La Jolla, CA

Meeting: 2019 ACR/ARP Annual Meeting

Keywords: human leukocyte antigens (HLA), major histocompatibility complex (MHC), T cells and monoclonal antibodies, TCR

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Session Information

Date: Sunday, November 10, 2019

Session Title: T Cell Biology & Targets in Autoimmune & Inflammatory Disease Poster

Session Type: Poster Session (Sunday)

Session Time: 9:00AM-11:00AM

Background/Purpose: The activation of T helper cells requires cognate recognition of antigen-derived peptides presented by Major Compatibility Complex Class II (MHC II) molecules, which are encoded by the human leukocyte antigen gene complex (HLA)-DR, HLA-DP and HLA-DQ genes. Polymorphisms in the HLA-DR beta chain 1 gene HLADRB1 are highly associated with many autoimmune diseases. The HLA-DRB1 ‘Shared Epitope’ is the single most significant genetic risk factor for Rheumatoid Arthritis. Blockade of the interaction of HLA-DR with the TCR might inhibit activation of autoreactive T cells while preserve protective antigen presentation by other HLA molecules.

Methods: HLA-DR selective binding Fabs were identified from phage display libraries and cloned as IgG2sigma/kappa antibodies. The affinities of the anti-HLA-DR antibodies for HLA-DR1 or DR4 complexes were measured by Surface Plasmon Resonance (SPR). To evaluate the potency of anti-HLA-DR mabs in vitro, peptide-specific T cell hybridoma lines were cocultured with APCs expressing HLA-DR1 or DR4. In addition, a mixed lymphocyte reaction (MLR) assay was established via coculture of human CD4+ T cells with bone marrow-derived dendritic cells (BMDC) from human HLA-DR4 transgenic (Tg) mice. To evaluate the efficacy of anti-HLA-DR mabs in vivo, human HLA-DR4 Tg mice were immunized with hemagglutinin (HA) peptide and HA-specific T cell expansion was assessed by ex vivo stimulation.

Results: DR4B127 is an anti-HLA-DR monoclonal antibody with a ‘silent’ Fc (lacking effector function). It selectively binds to HLA-DR1 or DR4 in the presence of various antigen peptides (KD=9~146 nM) but does not binds to HLA-DP or HLA-DQ. Its binding epitope does not overlap with the MHC II/TCR interfaces. However, interaction of MHC II/CD4 could be affected. Unlike other anti-HLA-DR antibodies (e.g. L243), the binding of DR4B127 does not cause apoptosis of primary human B cells in vitro. Target-mediated internalization is observed for DR4B127 and other HLA-DR-binding antibodies in vitro, and internalization efficiency is correlated with binding affinity. DR4B127 dose-dependently inhibits HLA-DR1- or HLA-DR4-restricted, HA peptide-dependent or HLA-DR4-restricted, type II collagen (CII) peptide-dependent activation of T cell hybridoma cells. DR4B127 also inhibits a human T cell/ HLA-DR4 Tg mouse BMDC MLR.  DR4B127 demonstrated a short half-life with t1/2 < 24h in both HLA-DR4 Tg mice and cyno monkeys.  DR4B127 does not deplete B cells in HLA-DR4 Tg mice in vivo. However, quick loss of target engagement is observed as over 90% of total HLA-DR epitopes on B cells are not covered by antibody after 24h. Sustained exposure of DR4B127 by repeated dosing is sufficient to inhibit HA-specific T cell expansion in vivo, while single dose treatment is not efficacious.

Conclusion: DR4B127 is differentiated from other anti-HLA-DR mabs, demonstrating a unique binding epitope and non-depleting profile. Although short half-life and transient target engagement preclude further development as a therapeutic for autoimmune indications, DR4B127 may have utility as a research tool for selective uptake into HLA-DR-expressing cells.


Disclosure: F. Shen, Janssen Research, Johnson&Johnson, 1, 3, 4; K. Duffy, None; S. Becart, Janssen, 3; R. Kuhn, None; M. Swiecki, None; B. Jones, None; Y. Li, None; J. Hall, None; R. Malaviya, Janssen Research, Johnson&Johnson, 1, 3, 4, Janssen Research, Johnson&Johnson, 1, 3, 4; N. Felix, Janssen, 3; M. Zhou, None; S. Nagpal, Janssen Research & Development, 3, Janssen Research, Johnson&Johnson, 1, 3, 4, Johnson & Johnson, 1, 4; N. Rao, Janssen Research & Development, 3, Johnson & Johnson, 1, 3, 4.

To cite this abstract in AMA style:

Shen F, Duffy K, Becart S, Kuhn R, Swiecki M, Jones B, Li Y, Hall J, Malaviya R, Felix N, Zhou M, Nagpal S, Rao N. Blockade of Antigen-specific T Cell Activation by a Non-Depleting Anti-HLA-DR Monoclonal Antibody with a Unique Binding Epitope [abstract]. Arthritis Rheumatol. 2019; 71 (suppl 10). https://acrabstracts.org/abstract/blockade-of-antigen-specific-t-cell-activation-by-a-non-depleting-anti-hla-dr-monoclonal-antibody-with-a-unique-binding-epitope/. Accessed April 13, 2021.
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