injections every 4 weeks, gradually increasing up to 150 mg every 8 weeksC Three brief episodes of fever, not temporally related to Canakinumab br / C no systemic and joint symptoms at 18 month follow-upLo Gullo et al

injections every 4 weeks, gradually increasing up to 150 mg every 8 weeksC Three brief episodes of fever, not temporally related to Canakinumab br / C no systemic and joint symptoms at 18 month follow-upLo Gullo et al., 2014n. 2015). Open in a separate window FIGURE 2 (A) Steric complementarity between Canakinumab and IL-1. Canakinumab (gray) binding to IL-1 (blues) largely obeys a lock-and-key type mechanism, with contributions by all CDRs and without any large structural changes of the paratope. (B,C) Hydrophobic potential of Canakinumabs Fab heavy and light chain. The surfaces are colored according to amino acid hydrophobicity. The hydrophobic residues (larger positive values of hydrophobicity) are maroon, while the hydrophilic residues (negative values of hydrophobicity) are cyan. The binding interface is remarkably flat, extensively hydrated, and very large. The IL-1 epitope does not include any aromatic or bulky hydrophobic residues. (2 B) surface epitope; (2 C) surface paratope. (D) All kind of interactions (polar and no polar, favorable) between Canakinumab and IL-1. The paratope residues that stand out in terms of number of intermolecular contacts to IL-1 are colored in yellow: Arginine (Arg) H101, Tryptophan (Trp) H52, Tyrosine (Tyr) H53, Tyr MMP7 H32 and Tyr L50. Arg H101 of the H-CDR3 loop plays an important role by forming strong electrostatic interactions with the epitope residue Glutamic acid (Glu) 64 (orange). Lysine (Lys) 27 (green) forms salt-bridge interactions. Canakinumab also has a high degree of species specificity. It does not bind to IL-1 from macaques, rodents, canines, and many other mammalian species, since the critical residue Glu 64 is not conserved in these species (Rondeau et al., 2015). Nevertheless, the same authors identified marmosets as the only nonhuman primate species that carries Glu 64 in its IL-1 (like the human IL-1) and demonstrated full cross-reactivity of Canakinumab, thereby enabling toxicological studies in this species. No toxicologically significant findings were detected (Martin and Bugelski, 2012). An embryo-fetal development study conducted in marmosets showed no major malformations but some slight skeletal variations at all dose levels of Canakinumab were suggestive of a delay in skeletal development. Due to its high affinity and specificity for IL-1, Canakinumab was considered suitable for therapeutic applications (Church and McDermott, 2009). The biological activity of this agent has been evaluated both and in animal models. The analysis showed a complete inhibition of IL-6 secretion stimulated by IL-1 in human UAMC 00039 dihydrochloride dermal fibroblasts (Alten et al., 2008). Church and McDermott (2009) assessed the neutralization of IL-1 activity by Canakinumab in a mouse model of joint inflammation. The treatment proved to provide protection against severe joint destruction, with no bone erosion detected compared to controls. Demonstration of pharmacodynamic action was conducted in preclinical mouse model NIH 3T3. Dawson and colleagues observed that UAMC 00039 dihydrochloride systemic intraperitoneal injections of Canakinumab in this model inhibit the neutrophil invasion in a dose-dependent manner (Gram, 2016). Mouse models for arthritis were used, instead, to validate the efficacy of Canakinumab. Study results demonstrated that Canakinumab can completely suppress IL-1-mediated joint inflammation and cartilage destruction in mice (Alten et al., 2008). In order to elucidate the molecular mechanism by which Canakinumab interferes with the IL-1, Rondeau et al. (2015) determined the crystal structures of the Canakinumab Fab in the free and IL-1-bound states. Canakinumab Fab subunits adopt the immunoglobulin fold and recognizes an extended, discontinuous epitope on human IL-1. The binding interface is flat, hydrated, and very large (Figures 2B,C). The X-ray analysis conducted by Rondeau et al. (2015) reveals a complex surface epitope with ordered water molecules at the Canakinumab-antigen interface. These molecules contribute to UAMC 00039 dihydrochloride the H-bonded network that connects epitope and paratope residues mediating shape/physico-chemical complementarity, improving the packing of atoms and allowing polar interactions. The amino acid composition of the paratope site is a balanced mix of hydrophobic aromatic, hydrophobic aliphatic, polar, and charged residues (Blech et al., 2013; Rondeau et al., 2015). The IL-1 epitope forms an extended, mostly planar, and hydrophilic surface (70% of all residues are polar or charged amino-acids). The combination of electrostatic interaction and shape complementarity plays a key role in the.