Protective effect of Bacillus Calmette-Guerin vaccine on rodent cerebral malaria

ObjectiveTo investigate the protective effect of Bacillus Calmette-Guerin vaccine(BCG)on rodent cerebral malaria.MethodsThe mice were treated with BCG 3 days after Plasmodium berghei ANKA(P.b ANKA)infection (P.b-3-B group)and only with P.b ANKA infection for the control group(P.b group).Parasitemia were monitored by Giemsa stained thin-smear microscopy.Flow cytometry was used to detect the subsets of splenic CD4⁺CD69⁺ T cells and CD4⁺CD25⁺Foxp3⁺ Treg cells on day 5 and 8 after the infection.The level of cytokine in the supernatant of splenocytes culture was measured by enzyme-linked immunosorbent assay(ELISA).Results The parasitemia of P.b-3-B group gradually increased from day 9 and 66.7% of the mice survived until day 19 and died at day 20 because of anemia.All mice in the control group died on day 8-10 because of cerebral malaria.On the day 5 and 8 after the infection,the percentage of CD4⁺CD69⁺T cells and interferon gamma(IFN-γ)level was 15.45% and 11.47%,550.24 pg/ml and 407.46 pg/ml,respectively,in P.b-3-B group,and significantly lower than those of the control group(17.74% and 15.42%,709.48 pg/ml and 600.37 pg/ml;P<0.05).However,the percentage of CD4⁺CD25⁺Foxp3⁺Treg cells and interleukin 10(IL-10)level was 10.03% and 15.18%,930.48 pg/ml and 265.87 pg/ml,respectively,in P.b-3-B group,and significantly higher than those of the control group(7.09% and 11.77%,603.3 pg/ml and 116.27 pg/ml;P<0.05).ConclusionBCG can reduce incidence of cerebral malaria by decreasing the intension of inflammatory response and prolong host survival.