Proteomics is a powerful approach to understanding what role proteins play in disease development, growth, treatment, and recovery. Most proteome research is focused on analyzing plasma and serum, as well as studying cell signaling pathways in cancer. However, saliva and urine matrices are gaining attraction due to the relatively simple, non-invasive collection method that can be performed anywhere. Identifying immunoglobulins (IgG) associated with specific pathological conditions has numerous potential applications in the diagnosis and monitoring of disease states as well in personalized medicine. Saliva is a complicated heterogenic matrix that can differ greatly between individuals in relation to age, genetics, viscosity, and the microbiome of the oral cavity (mucins, enzymes, and antibodies). Accurately defining the sample procedure to capture the dynamic range of analytes is also a major challenge. Hettegger et al. overcame this challenge by utilizing a peptide microarray platform that facilitated multiplexing samples with varying antibody titers from participants. Paired samples from 20 individuals were analyzed on epoxide microarrays containing 158 peptides from the Epstein Barr Virus (EBV) and 98 of Hepatitis B Virus (HBV). They determined that a subset of IgG antibodies displayed equal titers in blood and saliva. Most samples tested had high accordance using Pearson’s correlation of signal intensities (fluorescence) between the two sample types and based upon the quantitative microarray data from each sample, they demonstrated the diagnostic potential of saliva antibody titer and its’ potential relation to plasma titers.
Learn more here: https://doi.org/10.1371/journal.pone.0218456