Proteomic analysis of canine vaccines

To use proteomic analysis to identify qualitatively and quantitatively mammalian protein components of commercial veterinary vaccines against canine distemper, leptospirosis, borreliosis, and rabies.

25 licensed veterinary vaccines (from 4 different manufacturers) against canine distemper and leptospirosis, borreliosis, and rabies (3-year and 1-year durations of immunity).

Duplicate samples from a single-lot vial of each vaccine were prepared by acetone precipitation and proteolysis with trypsin and Lys-C protease mix. Peptides mixtures (1 μg) were analyzed by liquid chromatography-tandem mass spectrometry using an Orbitrap Fusion Lumos mass spectrometer. Liquid chromatography-tandem mass spectroscopy data were searched against a Bos taurus protein database using MaxQuant to identify and quantify mammalian proteins in the vaccines. Identified proteins were classified by function and network analysis to visualize interactions.

The largest number of mammalian proteins was identified in 3-year rabies vaccines (median, 243 proteins; range, 184 to 339 proteins) and 1-year rabies vaccines (median, 193 proteins; range, 169 to 350 proteins). Borrelia and leptospirosis-distemper (L&D) vaccines had the lowest number of proteins. Rabies vaccines had the highest number of identified proteins in common (n = 316); 33 were unique to 1-year products and 44 were found in 3-year products. Borrelia and L&D vaccines had 16 and 22 uniquely identified proteins, respectively. The protein classifications were primarily modulators of protein-binding activity, enzymes, transfer-carrier proteins, cytoskeletal proteins, defense-immunity proteins, calcium-binding proteins, and extracellular matrix proteins.

This study demonstrates proteomics application to evaluate quality differences among different vaccines, identifying potential stimulants of desirable and undesirable immune responses.