A) To determine non-specific lipid adherence to proteins, events with equivalent m/z and retention time values generate intensity ratios for lipids eluted from CD1 protein versus equivalently sized MHC proteins, which lack lipid binding clefts. B) The total number of CD1-associated features was corrected to remove events with characteristics of false positive or redundant detection of isotopes, alternate adducts and ion finding artifacts, yielding the number of unique events associated with each CD1 protein. C) Analysis of the linked and unlinked CD1 lipidomes yielded similar patterns for the number of ligands bound to each CD1 protein and similar percentages of lipids binding to 1, 2, 3 or 4 isoforms. Results in A-C are representative of two experiments for each protein set.