posted on 2015-11-17, 00:00authored byCrystal
S. F. Cheung, Kyle W. Anderson, Kenia
Y. Villatoro Benitez, Mark J. Soloski, John N. Aucott, Karen W. Phinney, Illarion V. Turko
The Borrelia burgdorferi spirochete
is the causative agent of Lyme disease, the most common tick-borne
disease in the United States. The low abundance of bacterial proteins
in human serum during infection imposes a challenge for early proteomic
detection of Lyme disease. To address this challenge, we propose to
detect membrane proteins released from bacteria due to disruption
of their plasma membrane triggered by the innate immune system. These
membrane proteins can be separated from the bulk of serum proteins
by high-speed centrifugation causing substantial sample enrichment
prior to targeted protein quantification using multiple reaction monitoring
mass spectrometry. This new approach was first applied to detection
of B. burgdorferi membrane proteins
supplemented in human serum. Our results indicated that detection
of B. burgdorferi membrane proteins,
which are ≈107 lower in abundance than major serum
proteins, is feasible. Therefore, quantitative analysis was also carried
out for serum samples from three patients with acute Lyme disease.
We were able to demonstrate the detection of ospA, the major B. burgdorferi lipoprotein at the level of 4.0 fmol
of ospA/mg of serum protein. The results confirm the concept and suggest
that the proposed approach can be expanded to detect other bacterial
infections in humans, particularly where existing diagnostics are
unreliable.