Identification of a Strongly Activating Human Anti-CD40 Antibody That Suppresses HIV Type 1 Infection

Abstract

We characterized the functional properties of a novel set of human anti-CD40 monoclonal antibodies originating from a human phage display library and identified an antibody that strongly activates cells via the CD40 receptor for potential use in HIV therapy. The anti-CD40 antibodies were converted from a single chain antibody fragment format (scFv) to an IgG format and produced in HEK293 cells, and the binding characteristics were evaluated. Next, their ability to (1) rescue a human B cell line from induced apoptosis, (2) stimulate B cell proliferation, and (3) block the CD40-CD40L interaction was determined. Finally, the most activating anti-CD40 antibody was tested for its ability to block HIV-1 infection in a monocyte-derived cell line. The different anti-CD40 antibodies, A24, B44, E30, F33, and A2-54, displayed a wide variety of binding and functional properties. In particular, B44 showed a very strong ability to activate normal human B cells and, in addition, did not block the CD40-CD40L interaction. This antibody was able to suppress HIV-1 infection in a human cell line (MonoMac 1) and may be a potential therapeutic candidate in HIV infection.

The Human Agonistic CD40 Antibody ADC-1013 Eradicates Bladder Tumors and Generates T-cell–Dependent Tumor Immunity

“…23) and B44 (19) were produced by transient expression in HEK cells and subsequent purification on protein A columns. An aglycosylated variant of ADC-1013, referred to as ADC-1013-N297Q, was produced by introducing a single N297Q mutation in the Fc-region.…”

“…To translate these findings into the clinic, we set out to engineer a CD40 agonistic antibody (18,19), ADC-1013, using Fragment INduced Diversity (FIND; ref. 20).…”

Phages and HIV-1: From Display to Interplay

“…In addition to targeting host receptors, a few studies reported the identification of peptides or antibody fragments directed against other host proteins such as cell surface determinants (CD) or intracellular enzymes [188,190,195,196]. The CD40 receptor, a member of the tumor necrosis factor receptor superfamily, and its CD40L ligand are involved in several biological processes including cell proliferation, activation and production of cytokines and chemokines.…”

“…In 2002, Ellmark et al identified a set of anti-CD40 antibody fragments through biopanning of a human ScFv phage library against a biotinylated CD40 antigen [189]. When expressed as full-length IgG1 one antibody (clone B44) suppressed HIV-1 infection by a R5-tropic virus, most probably through induction of CC chemokine production [188]. More recently, the DDX3 protein, a cellular RNA helicase involved in RNA unwinding was shown to play important roles in HIV-1 replication.…”