Identification and partial characterization of a gut Rhipicephalus appendiculatus cystatin

Saiki Imamura, Satoru Konnai, Shinji Yamada, Luís F. Parizi, Naftaly Githaka, Itabajara da S. Vaz, Shiro Murata, Kazuhiko Ohashi

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Vaccines are among the alternative tick control methods expected to replace at least in part the volumes of chemical acaricides currently used worldwide. However, a vaccination approach depends on a host immune response against proteins that are essential to tick physiology. The cystatin family is a protein class recently investigated to compose an effective antigen in a tick vaccine. In this study, a cDNA from Rhipicephalus appendiculatus with high sequence similarity to cystatins type 2 was identified by random sequencing analysis and called R. appendiculatus cystatin 1 (Ra-cyst-1). DNA sequence analysis showed that the cloned Ra-cyst-1 has a 423-bp open reading frame and codified to a 140-amino acid polypeptide. The putative mature protein consists of 115 amino acid residues with a deduced molecular weight of 12.8. kDa. The highly conserved G (P-I), QxVxG (P-II), and PW (P-III) type 2 cystatins motifs are present in Ra-cyst-1 cDNA. RT-PCR analysis showed that the Ra-cyst-1 gene is expressed in nymph, male, and female midgut following blood feeding, but not in the salivary glands of fed females. In addition, Western blot revealed that recombinant Ra-cyst-1 was not recognized by sera derived from rabbits infested with ticks, suggesting that this cystatin is not secreted into the host during infestation. We hypothesize that Ra-cyst-1 may play a role in the tick feeding process and could be a concealed antigen candidate in further anti-tick vaccination trials.

Original languageEnglish
Pages (from-to)138-144
Number of pages7
JournalTicks and Tick-borne Diseases
Volume4
Issue number1-2
DOIs
Publication statusPublished - 2013 Feb

Keywords

  • Anti-tick vaccine
  • Cystatin
  • Rhipicephalus appendiculatus

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Insect Science
  • Infectious Diseases

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