IL-12 is a member of the IL-12 family, which includes IL-12, IL-23, IL-27, and IL-35. Like other IL-12 family members, IL-12 is a heterodimeric cytokine. IL-12 is encoded by two separate genes, IL-12A (p35) and IL-12B (p40). The active heterodimer, and a homodimer of p40 are formed following protein synthesis. IL-12 is involved in the differentiation of naive T cells into Th1 cells. It is known as a T cell-stimulating factor, which can stimulate the growth and function of T cells. It stimulates the production of IFN-gamma and TNF-alpha from T and natural killer (NK) cells, and reduces IL-4 mediated suppression of IFN-gamma.

Alternate Names - IL12B, CLMF, CLMF2, IL-12B, IMD28, NKSF, NKSF2, IMD29, Interleukin 12 subunit beta, interleukin 12B, IL-12p40

IL-12 p40 Homology Across Species
Gallus gallus (chicken) IL-12 p40 - 100%
Coturnix japonica (Japanese quail) IL-12 p40 – 96%
Meleagris gallopavo (turkey) IL-12 p40 – 96%
https://blast.ncbi.nlm.nih.gov/