The 22nd chromatography component (F22) of the Fasciola gigantica excretory-secretory products (FgESP) shows better diagnostic value than the FgESP, and diagnostic methods based on F22 have also been established. Thus, exploring its immunomodulatory function and potential as a molecular vaccine candidate is attractive. In the present study, the effect of F22 on the mitogen-induced proliferation of buffalo peripheral blood mononuclear cells (PBMCs) in the innate immune response was preliminarily studied using the FgESP as a control. PBMCs were incubated with concanavalin A (ConA) and phytohemagglutinin (PHA) at optimal (1 µg/well) or suboptimal (0.25 µg/well) doses coupled with FgESP and F22 at different doses (1–16 µg/well). Cell proliferation was then assessed by microenzyme reaction colorimetry (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay). In addition, the components of F22 were also explored by mass spectrometry and then subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis to infer their functions. The results indicated that FgESP decreased the proliferation of PBMCs stimulated with ConA and PHA at specific doses, whereas F22 significantly decreased the proliferation of PBMCs stimulated with ConA and PHA at both optimal and suboptimal doses (p < 0.05). Two hundred and sixteen proteins were identified in F22, and these included 86 proteins that could be assigned to more than one pathway and some with robust immunomodulatory ability. Further studies should be performed to investigate the immunomodulatory function of F22 in the adaptive immune response, and the components of F22 can be further studied as potential vaccine candidate molecules.

Background: Milk is the primary nutrition source for mammalian infants. Production of milk varies among species, breeds within the same species or even individuals of the same breed. Despite large variations in milk production (e.g. yield, composition), the health of recipient infants remains unperturbed regardless of species, breeds or individuals, suggesting a compensatory mechanism for low milk production to offset the potential nutrition difference compared with high milk production. Methods: Here, we profiled and compared the milk exosomal microRNAs between groups with low and high milk production in two buffalo breeds. Result: We found that individuals with low milk production mainly down-regulated microRNAs targeting the genes in protein digestion and absorption pathway. Given that milk exosomal microRNAs could be taken up by the epithelial cells of infants, down-regulation of which inhibits expression of genes encoding proteins responsible for protein digestion, peptides and amino acid transportation in infants’ digestive system. Such down-regulation of genes facilitates the protein digestion, peptide absorption and amino acid absorption (e.g. stomach, intestine, colon) for infants. Our results thus provide a novel insight that exosomal microRNAs may play an important role in balancing the nutrient absorption of infants between mothers with low milk production and ones with high milk production.

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