Interleukin-12 and Interleukin-23 (IL-12 and IL-23)

Interleukin-12 and Interleukin-23 are closely related, heterodimeric cytokines of the interleukin family. Both share the p40 protein subunit but have unique secondary subunits—p35 for IL-12 and p19 for IL-23. Their receptors also share structural components: IL-12 signals through a heterodimeric receptor complex of IL-12Rβ1 and IL-12Rβ2, while IL-23 uses IL-12Rβ1 and IL-23R[1][3][4][5][8]. IL-12 primarily induces and amplifies the Th1 immune response, crucial for defense against intracellular pathogens and tumor cells, while IL-23 is essential for the differentiation and maintenance of Th17 cells, which are involved in defense against extracellular bacteria and autoimmunity[2][4][5]. Dysregulation of the IL-12/IL-23 axis contributes to chronic inflammatory and autoimmune diseases, as well as certain cancers. Therapeutics such as monoclonal antibodies targeting the shared p40 subunit have demonstrated efficacy in multiple immune-mediated conditions (e.g., Crohn’s disease), but long-term modulation of these pathways can have significant immune system consequences[6][7]. There is nothing incorrect or ambiguous about the inclusion of these targets; however, the term "IL-12 and IL-23" refers to two related but distinct cytokines frequently targeted together due to their shared p40 subunit and overlapping roles in pathology and therapeutics[6].

Other names

IL-12IL-23Interleukin 12Interleukin 23IL-12p70 (specifically for IL-12 heterodimer)IL-12p40 and IL-12p35 (subunits of IL-12)IL-23p19 and IL-12p40 (subunits of IL-23)

Inhibition of cytokine-receptor interaction (blocking p40 subunit prevents both IL-12 and IL-23 activity); Blockade of JAK/STAT signaling downstream of IL-12/IL-23 receptors; Reduction of Th1/Th17 cell differentiation and function.