Interleukin-12 (IL-12):
Structure: Heterodimeric cytokine composed of p35 and p40 subunits
Mainly produced by: Dendritic cells, macrophages, neutrophils
Promotes differentiation of naive T cells into Th1 cells
Enhances the cytotoxic activity of NK cells and CD8+ T cells
Stimulates IFN-γ production
Role in immunity: Critical for cell-mediated immunity against intracellular pathogens
Interleukin-23 (IL-23):
Heterodimeric cytokine composed of p19 and p40 subunits (shares p40 with IL-12)
Produced by activated dendritic cells and macrophages
Promotes differentiation and maintenance of Th17 cells
Stimulates production of IL-17, IL-22, and TNF-α
Important for mucosal immunity and inflammation
Both are members of the IL-12 family of cytokines
Share the p40 subunit but have distinct biological activities
IL-12 primarily drives Th1 responses, while IL-23 promotes Th17 responses
Dysregulation of IL-12 and IL-23 is implicated in various autoimmune and inflammatory disorders.
Therapeutic targeting of these cytokines has shown promise in treating conditions like psoriasis, inflammatory bowel disease, and rheumatoid arthritis.
The IL-12 and IL-23 cytokines play a critical role in homeostasis and inflammation in the intestinal tract.
They share various features, including a common
p40 cytokine subunit, a common interleukin12 R receptor sub unit and Manus Kinase signal transducer and activator of transcription(STAT) signaling molecule that communicates downstream functions.
Drugs that inhibited either the shared interleukin– 12 p40 sub unit or the selective interleukin 23 p19 subunit are utilized for treatment for Crohn’s disease
Interleukin-12 is involved in the differentiation of T cells to Th1 cells which are increased in Crohn’s disease: its inhibition, therefore reduces level of intestinal Th1 cells and reduces inflammation.
Interleukin12 p40 also associates with Interleukin 23 p19 to form interleukin 23 which expands and maintains Th17 cells.