Role of the carbohydrate moiety in determining the survival of interferon in the circulation

The role of the carbohydrate moiety in influencing the survival time of human lymphoblastoid interferon in the rat circulation was monitored at varying time intervals after intravenous injection. The serum survival time of native interferon was drastically reduced by prior enzymatic cleavage of the terminal sialic acid residues to yield the galactose-terminal product, asialo-interferon. This phenomenon was completely reversed by further extensive digestion with a mixture of glycosidases which effectively removed over 85% of the total carbohydrate residues. These results suggest that the intact carbohydrate structure is neither essential for normal circulation time in vivo nor for biologic activity in vitro.