Anti-IL2 Monoclonal antibody, clone C-H6

Rabbit hemorrhagic disease (RHD) is a highly contagious infection that has caused significant damage to the rabbit industry since 1984. Inactivated vaccines, the currently used prevention measures, are effective in controlling RHD. However, these vaccines are derived from the livers of infected rabbits, which constitutes a major concern in terms of animal welfare and safety. Administration of DNA vaccines in collaboration with appropriate adjuvants, in particular, cytokines, to strengthen the immune response presents a novel optimization strategy to generate more efficient vaccines. In this study, the adjuvant effect of interleukin (IL)-2 co-expression with the VP60 gene in a DNA vaccine was evaluated. In total, four groups of 60 RHD virus (RHDV)-free rabbits (30 days old) were orally or subcutaneously administered recombinant SL7207-pVAX1-IL2-VP60, SL7207-pVAX1-VP60, SL7207-pVAX1 bacteria or the commercial inactive vaccine, and the induced immunity evaluated by challenge with the RHDV(Y8504/China) strain on day 56. The Recombinant SL7207-pVAX1-IL2-VP60 induced a higher level of antibodies than the vaccine SL7207-pVAX1-VP60 and inactivated vaccines to a significant extent. The concentrations of interleukin (IL)-4 were markedly higher than those in groups immunized with the naked or inactive vaccine alone. Furthermore, the fusion gene vaccine provided higher protection (93.33%) after virus challenge relative to immunization with the single gene (SL7207-pVAX1-VP60). The collective results indicate that recombinant SL7207-pVAX1-IL-2-VP60 bacteria exert enhanced protective effects against RHDV and therefore present a strong candidate as a potential vaccine. Moreover, IL-2 enhanced both humoral and cellular responses, highlighting the utility of rabbit IL-2 as an effective adjuvant.

The programmed cell death 1 (PD-1) pathway represents a major immune checkpoint, which may be engaged by cells in the tumor microenvironment to overcome active T-cell immune surveillance. Pembrolizumab (Keytruda (R), MK-3475) is a potent and highly selective humanized mAb of the IgG4/kappa isotype designed to directly block the interaction between PD-1 and its ligands, PD-L1 and PD-L2. This blockade enhances the functional activity of T cells to facilitate tumor regression and ultimately immune rejection. Pembrolizumab binds to human and cynomolgus monkey PD-1 with picomolar affinity and blocks the binding of human and cynomolgus monkey PD-1 to PD-L1 and PD-L2 with comparable potency. Pembrolizumab binds both the CD and FG loops of PD-1. Pembrolizumab overcomes human and cynomolgus monkey PD-Li-mediated immune suppression in T-cell cultures by enhancing IL2 production following staphylococcal enterotoxin B stimulation of healthy donor and cancer patient cells, and IFN gamma production in human primary tumor histoculture. Ex vivo and in vitro studies with human and primate T cells show that pembrolizumab enhances antigen-specific I'-cell 1FN gamma and 1L2 production. Pembrolizumab does not mediate FcR or complement-driven effector function against PD-1-expressing cells. Pembrolizumab displays dose-dependent dearance and half-life in cynomolgus monkey pharmacoldnetic and toxicokinetic studies typical for human lgG4 antibodies. In nonhuman primate toxicology studies, no findings of toxicologic significance were observed. The preclinical data for pembrolizumab are consistent with the clinical anticancer activity and safety that has been demonstrated in human clinical trials.