Canine Tumour Necrosis Factor alpha (TNF alpha) is produced by a range of cells, including macrophages and monocytes and is an important mediator of the canine inflammatory response.

129-20124 has an ED₅₀ of 10pg/ml, determined by measuring the cytolytic effect of recombinant canine TNF alpha on murine WEHI-13VAR-164 cells in the presence of Actinomycin D.