Identification of Cytauxzoon felis antigens via protein microarray and assessment of expression library immunization against cytauxzoonosis

Schreeg, Megan E., Marr, Henry S., Tarigo, Jaime L., Sherrill, Meredith K., Outi, Hilton K., Scholl, Elizabeth H., Bird, David M., Vigil, Adam, Hung, Chris, Nakajima, Rie, Liang, Li, Trieu, Angela, Doolan, Denise L., Thomas, Jennifer E., Levy, Michael G., Reichard, Mason V., Felgner, Phillip L., Cohn, Leah A., and Birkenheuer, Adam J. (2018) Identification of Cytauxzoon felis antigens via protein microarray and assessment of expression library immunization against cytauxzoonosis. Clinical Proteomics, 15. 44.

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Background: Cytauxzoonosis is a disease of felids in North America caused by the tick-transmitted apicomplexan parasite Cytauxzoon felis. Cytauxzoonosis is particularly virulent for domestic cats, but no vaccine currently exists. The parasite cannot be cultivated in vitro, presenting a significant limitation for vaccine development.

Methods: Recent sequencing of the C. felis genome has identified over 4300 putative protein-encoding genes. From this pool we constructed a protein microarray containing 673 putative C. felis proteins. This microarray was probed with sera from C. felis-infected and naïve cats to identify differentially reactive antigens which were incorporated into two expression library vaccines, one polyvalent and one monovalent. We assessed the efficacy of these vaccines to prevent of infection and/or disease in a tick-challenge model.

Results: Probing of the protein microarray resulted in identification of 30 differentially reactive C. felis antigens that were incorporated into the two expression library vaccines. However, expression library immunization failed to prevent infection or disease in cats challenged with C. felis.

Conclusions: Protein microarray facilitated high-throughput identification of novel antigens, substantially increasing the pool of characterized C. felis antigens. These antigens should be considered for development of C. felis vaccines, diagnostics, and therapeutics.

Item ID: 56926
Item Type: Article (Research - C1)
ISSN: 1559-0275
Keywords: cytauxzoonosis, Cytauxzoon felis, expression library immunization, protein microarray, piroplasmid, vaccine
Copyright Information: This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.
Date Deposited: 25 Jan 2019 01:19
FoR Codes: 32 BIOMEDICAL AND CLINICAL SCIENCES > 3204 Immunology > 320499 Immunology not elsewhere classified @ 100%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920109 Infectious Diseases @ 100%
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