Genetic conservation of Cytauxzoon felis antigens and mRNA expression in the schizont life-stage

• Published in: Veterinary parasitology Vol. 263; pp. 49 - 53
• Main Authors: Khana, Daven B., Peterson, David S., Stanton, James B., Schreeg, Megan E., Birkenheuer, Adam J., Tarigo, Jaime L.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.11.2018
• Subjects: Animals; Antigen; Antigens, Protozoan - genetics; Cat Diseases - parasitology; Cats; Cytauxzoon felis; Cytauxzoonosis; DNA, Protozoan - genetics; Feline; Genetic conservation; Piroplasmida - genetics; Protozoan Infections, Animal - mortality; Protozoan Infections, Animal - parasitology; Protozoan Infections, Animal - prevention & control; Protozoan Vaccines - genetics; Protozoan Vaccines - immunology; RNA, Messenger - genetics; Schizonts - genetics; Vaccine candidate; Antigen; Vaccine candidate; Cytauxzoonosis; Feline; Cytauxzoon felis; Genetic conservation
• ISSN: 0304-4017; 1873-2550
• DOI: 10.1016/j.vetpar.2018.10.007

•Nucleotide and amino acid sequence conservation is 99–100% amongst vaccine candidates.•The vaccine candidates were predicted to have one or more transmembrane helices.•The vaccine candidates were predicted to have no signal peptide cleavage sites.•The vaccine candidates are robustly expressed in the schizont life-stage of C. felis. Cytauxzoonosis is a highly fatal disease of domestic cats caused by the apicomplexan protozoan Cytauxzoon felis, which is most closely related to Theileria spp. The growing prevalence, high morbidity and mortality, and treatment cost of cytauxzoonosis emphasize the need for vaccine development. Traditional approaches for vaccine development, however, have been hindered by the inability to culture C. felis in vitro. Recent availability of the annotated C. felis genome combined with genome-based vaccine design and protein microarray immunoscreening allowed for high-throughput identification of C. felis antigens that could serve as vaccine candidates. This study assessed the suitability of three of these vaccine candidates (cf30, cf63, cf58) in addition to a previously reported vaccine candidate (cf76) based on two criteria: genetic conservation among diverse C. felis geographic isolates and expression in tissues containing the C. felis schizont life stage, which has been previously associated with the development of a protective immune response. A comparison of seventeen C. felis isolates across seven states demonstrated high sequence identity (99–100%) for cf30, cf63, and cf58, similar to the degree of conservation previously reported for cf76. RNAscope® in situ hybridization using acutely infected feline splenic tissue revealed robust levels of all transcripts in the schizont life stage of the parasite. These data support the suitability of these three antigens for further investigation as vaccine candidates against cytauxzoonosis.