T-cell growth factor production and protein synthesis

It is known that protein synthesis inhibitors (PSI) do not block production of some immunoregulatory and inflammatory mediators. Here we show that the production of T-cell growth factor (TCGF) by phytohaemagglutinin-stimulated human peripheral blood lymphocytes (PBL) was resistant to inhibition of protein synthesis more than 90-95%. Moreover, TCGF production was significantly accentuated in the presence of low concentrations of PSI in cultures from low- and high-producer donors. The presence of macrophages was non-essential for enhancement of TCGF production by PSI. When high doses of PSI were used, TCGF production was inhibited. In contrast, the synthesis of granulocyte/macrophage colony-stimulating factor (CSF) was blocked in the presence of low concentration of PSI. Hence, the results indicate that human TCGF produced by PBL belongs to a group of soluble factors whose production is relatively resistant to the action of PSI.