Serum metabolism-transcriptomics investigated into the immunity of whey protein isolate-galacto-oligosaccharide conjugates after dynamic high-pressure microfluidics pretreatment.

The objective of this study was to investigate the immunomodulatory effects of whey protein isolate (WPI)-galacto-oligosaccharide conjugates following dynamic high-pressure microfluidics pretreatment (DHPM) in cyclophosphamide-induced immunosuppressed mice. DHPM facilitated the conjugation of WPI and galacto-oligosaccharide, and inhibited the generation of fluorescent advanced glycation end products (AGEs) and pentosidine. The conjugates demonstrated a significant immune recovery effect on CTX-induced immunosuppressed mice, as evidenced by the enhancement of IgG antibody levels (from 3.5 to 4.1) and the reduction of the levels of immunosuppressive effector factors TGF-β (from 148.1 to 111.2) and IFN-γ (from 34.4 to 17.9). Furthermore, the conjugates exhibited a notable ability to repair histological lesion in the spleen of CTX-induced immunosuppressed mice. Spleen transcriptomics revealed that the Marco, Klrc3 and Cd209b genes were associated with the immune enhancement activity of the conjugates. Metabolomic analysis identified arginine biosynthesis, sphingolipid metabolism, alanine, aspartate and glutamate metabolism, and phenylalanine, tyrosine and tryptophan biosynthesis as key pathways in the immune enhancement activity of the conjugates. Metabolomics combined with transcriptomics indicated the importance of macrophage activation in the restoration of immunosuppressed mice's immunity by the conjugates. Therefore, the improvement in immunity observed with WPI-galacto-oligosaccharide conjugates may be related to the activation of macrophages.