Figure 3. Early administration of BCG to human newborns in vivo altered the plasma lipidome. Network reconstruction of BCG-altered metabolic pathways demonstrated perturbation of lipid metabolism.

(A) Over half of identified metabolites induced by newborn BCG vaccination belonged to the lipid class, followed by amino acids. Among the significantly altered lipids, 70% (24 identified metabolites) of the lipids belonged to the lysophospholipid (LPL) subclass. Data are presented as counts of significant lipids.

(B) Examples of significantly different lipid metabolites between the early versus delayed BCG groups. Boxplots display medians with lower and upper hinges representing first and third quartiles; whiskers reach the highest and lowest values no more than 1.5× interquartile range from the hinge. Welch’s t test was used for data analysis. Data presented are the scaled, normalized peak intensities of the metabolites. *p < 0.05; **p < 0.01 versus control.

(C) Pathway-based network reconstruction of DAMs from 4-week-old infants vaccinated with BCG in the first week of life compared with the delayed BCG group. The illustrated lipid pathways include lipid biosynthesis pathways (steroid hormone, fatty acid, androgen and estrogen, and cholesterol), glycerophospholipid, glycosphingolipid, omega 6-fatty acid, prostaglandin, and arachidonic acid metabolism. Legend key represents detected metabolites, levels comparing early versus delayed BCG: down (blue), up (red), white (unchanged), and gray (undetected), with their log₂ fold-change values.