In the present study, a semiquinone g
lucoside derivative (SQGD) iso
lated from a radioresistant bacterium Baci
llus sp. INM-1 was eva
luated for its immunostimu
latory activities. Human periphera
l b
lood mononuc
lear ce
lls (PBMCs) were stimu
lated by different doses (30–90 μg/m
l) of SQGD for different time (3–12 h) interva
ls at 37 °C, and IL-12p40, IL-23p19, IL-10, Re
lA and c-Jun gene expression ana
lysis was carried out by qRT-PCR method. SQGD dose dependent cytokines protein expression kinetic ana
lysis was carried out using western b
lotting. As the resu
lts of SQGD (30 μg/m
l) stimu
lation for 3 h at 37 °C, significant induction in IL-12p40, IL-23p19 and Re
lA gene expression was observed in PBMCs compared to unstimu
lated contro
l ce
lls. However, no such induction in IL-10 and c-Jun gene expression was observed. Time dependent protein expression study indicated significant increase in IL-12p40, IL-12p35, IL-23p19 and Re
lA protein expression at 3–6 h, which was found decrease at 12 h upon SQGD treatment. In contrast, IL-10 protein expression was found to enhance significant
ly at 12 h after SQGD treatment to the PBMCs. SQGD dose dependent study showed approximate
ly simi
lar
leve
l of induction in IL-12p40, IL-12p35, IL-23p19 and Re
lA proteins expression at a
ll tested concentration (30–90 μg/m
l) compared to contro
l. However, no significant change in the IL-10 and c-Jun protein expression was observed at any SQGD concentration. SQGD treatment (0.25 mg/kg b wt.) was a
lso found to enhance anti-keyho
le Limpet Hemocynin (KLH) IgM antibodies significant
ly in the mice immunized by KLH.
Thus, SQGD fraction stimulates cellular immunity by inducing immunostimulatory cytokines and humoral immunity by enhancing IgM antibodies and could be a promising immunostimulant. Further studies related to molecular mechanisms offering immunostimulation is underway, will certainly helpful to unravel its mode of action in the biological system.