This is a human IgG1 monoclonal antibody using the same sequences as the therapeutic antibody guselkumab. It specifically targets the p19 alpha subunit of interleukin-23 (IL23), an inflammatory cytokine which activates the CD4+ T-helper cell pathway to mediate the inflammatory cascade that induces psoriatic plaque formation. While IL23 promotes the normal inflammatory and immune responses, the p19 and p40 subunits of IL23 are found to be over-expressed in the conditions of psoriasis and other autoimmune inflammatory skin diseases. Guselkumab selectively binds to the p19 subunit of IL23 in dendritic cells and keratinocytes, effectively inhibiting its interaction with the IL23 receptor. Consequently, this blockade prevents the release of other pro-inflammatory cytokines and chemokines through stimulation of immune cells such as Th17 cells.