In vitro effect of lentinan on the activation of immunological cells in Cyprinus carpio

Abstract

Macrophages from the head kidney (HK) and peripheral blood leucocytes were isolated fromCyprinus carpio by Percoll gradient density centrifugation, cultured in vitro and exposed to different concentrations of the immunomodulator lentinan. To evaluate the immunostimulating effects of lentinan, proliferation of the peripheral blood leucocytes, respiratory burst of macrophages and interleukin-1β (IL-1β) gene mRNA expression of macrophages were investigated by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide], NBT (nitroblue tetrazolium) reduction, Griess reaction and real-time polymerase chain reaction (PCR). Results showed that proliferation of peripheral blood leucocytes after 24 h incubation by the induction of lentinan at 100 and 1000 μg/ml was markedly stimulated. Lentinan at 1, 100 and 1000 μg/ml could significantly induce superoxide anions in macrophages. Production of nitric oxide by HK macrophages after 96 h incubation by lentinan showed that it had no conspicuous effect on nitrogen burst activity of macrophages. Moreover, it inhibited the nitrogen burst activity at higher doses. The expression of IL-1β in the HK macrophages after 24 h of polysaccharide stimulation showed that lentinan stimulated IL-1β expression in the head kidney in carp. Lentinan can modulate the immune response of C. carpio.