Vaccination Effects of Recombinant Chitinase Protein from the Hard Tick Haemaphysalis longicornis (Acari: Ixodidae)

Abstract

ABSTRACT. The success of immunological method for the control of ticks depend on the use of potential key antigens as tick vaccine candidates. Chitinase is induced by ecdysteroids to degrade the older chitin at the time of molting. Previously, we cloned a gene encoding 113 kDa protein (CHT1) of Haemaphysalis longicornis, and identified the CHT1 as a protein of chitinase (You et al. 2003). In this study, the recombinant CHT1 (rCHT1) expressed in Escherichia coli was used to immunize mice. The mice were challenge-infested with ticks at different developmental stages of the same species. The rCHT1 stimulated a specific protective anti-tick immune response in the mice as evidenced by the significant longer feeding periods in the larval ticks and significant difference in the egg weights. The molting periods in the ticks fed on the rCHT1-immunized mice tended to be longer than those of the controls. Nymphal ticks fed on the rCHT1-immunized mice showed lower molting rate (76.7%) compared to 96.7% for the control. These results demonstrated that the rCHT1-immunized mice sera implicated on molting step, suggesting that the rCHT1 might be a useful vaccine candidate antigen for biological control of the tick.

In silico selection of functionally important proteins from the mialome of Ornithodoros erraticus ticks and assessment of their protective efficacy as vaccine targets

“…In the present study, we focused on midgut chitinases, tetraspanins and RPP0 because these proteins are involved in important midgut physiological processes; several publications highlight their potential as vaccine candidates to control parasite infections [28, 29, 33, 42]. Additionally, and despite their unknown functions, we also focused on secreted proteins/peptides because of their accessibility to host antibodies ingested in blood, which make them the first-election candidate antigens for tick vaccine design [69, 70].…”

“…These chitinases are differently expressed between developmental stages and tissues and play distinct functions [27]. In ticks, chitinases have been found in salivary glands, the midgut, ovaries, Malpighian tubules, synganglion and the epidermis, where they contribute to attaching and feeding, degradation of the chitinous endocuticle during moulting, and regulation of the turnover and porosity of the chitin-containing peritrophic matrix [24, 28–30]. Accordingly, tick chitinases have been considered as potential bioacaricides and vaccine targets for tick control [28, 31].…”

“…In ticks, chitinases have been found in salivary glands, the midgut, ovaries, Malpighian tubules, synganglion and the epidermis, where they contribute to attaching and feeding, degradation of the chitinous endocuticle during moulting, and regulation of the turnover and porosity of the chitin-containing peritrophic matrix [24, 28–30]. Accordingly, tick chitinases have been considered as potential bioacaricides and vaccine targets for tick control [28, 31]. More recently, RNAi gene knockdown of a chitinase of Amblyomma americanum was shown to reduce female feeding performance and fecundity [29].…”

Gene Expression in the Salivary Gland of Rhipicephalus (Boophilus) microplus Fed on Tick-Susceptible and Tick-Resistant Hosts

“…Insect cells usually express a number of β-Nacetylhexosaminidases, which are important in various developmental stages during their life cycle, primarily in the turnover of the chitin exoskeleton (Hogenkamp et al, 2008). According to You and Fujisaki (2009), molecules associated with molt act to protect organisms against pathogen invasion, on peritrophic membrane control and other functions necessary during blood feeding and molting in ticks and may be candidates for parasite control. In our results, a DEG similar to a β-N-acetylhexosaminidase and upregulated in ticks fed on tick-susceptible cattle was found in salivary glands.…”

“…microplus (Hackman, 1975). Ticks periodically shed their old cuticles and resynthesize new ones, a process that is mediated by the elaboration of chitinase in the molting fluid that accumulates between the old cuticle and the epidermis (You and Fujisaki, 2009). Female ticks of the Ixodidae family, in general, increase their mass up to 100-fold during the 7-10 days feeding period and synthesize sufficient endocuticle to thicken their cuticle by the end of the slow phase of engorgement (Flynn and Kaufman, 2015); thus, the inhibition of enzymes involved in chitin metabolism during morphogenesis might cause serious tick damage (Del Pino et al, 1998).…”