Characterization of a Broadly Reactive Anti-CD40 Agonistic Monoclonal Antibody for Potential Use as an Adjuvant

Abstract

Lack of safe and effective adjuvants is a major hindrance to the development of efficacious vaccines. Signaling via CD40 pathway leads to enhanced antigen processing and presentation, nitric oxide expression, pro-inflammatory cytokine expression by antigen presenting cells, and stimulation of B-cells to undergo somatic hypermutation, immunoglobulin class switching, and proliferation. Agonistic anti-CD40 antibodies have shown promising adjuvant qualities in human and mouse vaccine studies. An anti-CD40 monoclonal antibody (mAb), designated 2E4E4, was identified and shown to have strong agonistic effects on primary cells from multiple livestock species. The mAb recognize swine, bovine, caprine, and ovine CD40, and evoked 25-fold or greater proliferation of peripheral blood mononuclear cells (PBMCs) from these species relative to cells incubated with an isotype control (p<0.001). In addition, the mAb induced significant nitric oxide (p<0.0001) release by bovine macrophages. Furthermore, the mAb upregulated the expression of MHC-II by PBMCs, and stimulated significant (p<0.0001) IL-1α, IL6, IL-8, and TNF-α expression by PBMCs. These results suggest that the mAb 2E4E4 can target and stimulate cells from multiple livestock species and thus, it is a potential candidate for adjuvant development. This is the first study to report an anti-swine CD40 agonistic mAb that is also broadly reactive against multiple species.

Kaposi's Sarcoma-Associated Herpesvirus Latency Locus Renders B Cells Hyperresponsive to Secondary Infections

“…We expect that BALB/c latency mice are better at inducing Ig responses to adjuvanted antigens than BALB/c or BALB/c FKO mice. Anti-CD40 has been explored as a potent adjuvant in vaccine design (58,59). For instance, a vaccine against lymphoma consisting of an anti-CD40 antibody chemically coupled to the tumor idiotype, A20, inhibited tumor growth in a mouse lymphoma model (60).…”

The Effects of Checkpoint Blockade and a CD40 Agonist on Tindependent and T-dependent Antibody Responses in Mice: Implications for Optimization of Vaccination Strategies in Patients Receiving Immunotherapies

“…Likewise, the antibodies that interfere with PD-L1 binding to its receptor PD-1 interfere with T-cell exhaustion thereby enhancing T-cell reactivity to their cognate tumor antigens [8,9]. On the other hand, antibodies with agonist activity to co-stimulatory pathways such as the CD40/CD40L pathway can act as immunologic adjuvants that can enhance antigen presenting cells (APCs) such as dendritic cells, B cells, and cells of the monocyte-macrophage series [10]. Enhancement of antigen presentation to T and B lymphocytes leads in turn to enhanced and more durable immune responses to tumor antigens [11][12][13].…”