An extracellular glycoprotein exhibiting immune activity was produced
by Trichosporon pullulans yeast grown in a defined ethanol-containing
medium. The glycoprotein had a molecular mass of 100-150 kDa. The carb
ohydrate portion of the glycoprotein consisted of mannose as a predomi
nant component, glucose, and a small amount of arabinose. This glycopr
otein was named MAG. Immunological studies showed that MAG exhibited a
high immunomodulating activity, revealed distinct adjuvant properties
,had a wide therapeutic index, and increased non-specific resistance o
f mammals to infection. In batch culture, the most active MAG producti
on (36 4 mg l(-1)) coincided with the phase of active yeast growth. In
a chemostat under nitrogen limitation, the rate of the MAG synthesis
increased with increasing a specific growth rate. (C) 1998 Elsevier Sc
ience Ltd. Ail rights reserved.