Conclusion
B. longum showed the best protective effect against Plasmodium infection by reducing the degree of parasitemia and modulating the gut immunity. This provides a basis for further research involving probiotic supplementation in immunity modulation of infectious diseases.
Methods
P. berghei was inoculated intraperitoneally. Infected mice were randomly divided into 5 groups and treated with either L. casei, B. longum, or the combination of both for 5 days before up to 6 days post-infection (p.i). The control group was treated with phosphate-buffered saline (PBS), while uninfected mice were used as negative control. Levels of CD103 and forkhead box P3 (FoxP3) expression were measured by direct immunofluorescense, while plasma IFN-γ and TNF-α level were determined using enzyme-linked immunosorbent assay (ELISA).
Purpose
During Plasmodium berghei (P. berghei) infection, infected erythrocytes are sequestered in gut tissues through microvascular circulation, leading to dysbiosis. This study aimed to investigate the effect of Lactobacillus casei (L. casei) and Bifidobacterium longum (B. longum) administration on the parasitemia level, gut microbiota composition, expression of cluster of differentiation 103 (CD103) in intestinal dendritic and T regulatory cells (T reg), plasma interferon gamma (IFN-γ) and tumor necrosis factor (TNF-α) levels in P. berghei infected mice.
Results
All treated groups showed an increase in parasitemia from day 2 to day 6 p.i, which was significant at day 2 p.i (p = 0.001), with the group receiving B. longum displaying the lowest degree of parasitemia. Significant reduction in plasma IFN-γ and TNF-α levels was observed in the group receiving B. longum (p = 0.022 and p = 0.026, respectively). The CD103 and FoxP3 expression was highest in the group receiving B. longum (p = 0.01 and p = 0.02, respectively).