Effect of thymosin-alpha1 on the production of nitric oxide by tumor-associated macrophages

Abstract

The present investigation was conducted to study the effect of thymic peptide: thymosinα1 (thyα1) on the activation of tumor associated mφ (TAM) obtained from mice bearing a transplantable T cell lymphoma of spontaneous origin designated as Dalton's lymphoma, to produce nitric oxide (NO). It was found that in vivo administration of aqueous thymic extract obtained from thymus of normal mice or thyα1 could activate the TAM to produce enhanced amount of NO which was further augmented on in vivo treatment of these TAM by LPS. These observations suggest that thyα1 could prime TAM for activation by second signal of LPS. The study also presents evidence that tumor cell elaborate factors that enhance the effect of thyα1 on TAM for production of NO. This is the first study to show that thyα1 can activate TAM directly even in the absence of LPS, and may, therefore, have clinical significance.