Effect of vaccination with a recombinant metalloprotease from Haemaphysalis longicornis

Abstract

We report the cloning, expression and characterization of an Haemaphysalis longicornis metalloprotease (named HLMP1). The gene encodes a predicted 550 aminoacid protein with similarity to metalloproteases of the reprolysin family. The protein sequence contains a signal sequence, the zinc-binding motif (HEXXHXXGXXH) common to metalloproteases and a cysteine-rich region. Reverse transcription-PCR expression analysis indicates the presence of mRNA in the salivary gland of larva, nymph and adult ticks. Rabbit repeatedly infested with H. longicornis recognized rHLMP1, suggesting that the immune-response against HLMP1 is naturally induced through the feeding of ticks. Vaccination of rabbit with rHLMP1 produced protective immunity against ticks, resulting in 15.6 and 14.6% mortality in nymph and adult ticks, respectively. This work provides information to understand the tick's defense system, and offers new insights to develop strategies to block this defense system with an anti-tick vaccine based on a metalloprotease.

Expression profiling, gene silencing and transcriptional networking of metzincin metalloproteases in the cattle tick, Rhipicephalus (Boophilus) microplus

“…As previously mentioned, vaccination with single metzincins did in fact result in some decrease of engorgement weight and ovipositioning, however, it did not have a great effect on tick mortality (Decrem et al, 2007;Imamura et al, 2009). Based on the differential transcriptional network observed between reprolysins and astacins, the results support use of a combinatorial metzincin-based vaccine, which will be evaluated in a subsequent study.…”

“…Spirochete dissemination through vertebrate tissues may similarly be aided by salivary metalloproteases and other salivary anti-haemostatic agents (Maritz-Olivier et al, 2007;Ribeiro, 1989), which prevent fibrin clot formation and dissolution of the fibrin clots eventually formed around the feeding cavity of ixodid ticks (Francischetti et al, 2003). For this reason both Decrem et al (2007) and Imamura et al (2009) selected salivary gland metalloproteases from I. ricinus and H.…”

“…Accordingly, Decrem et al (2007) proposed that these salivary gland metalloproteases are adequate vaccine candidates, since an elicited antibody response would result in the inhibition of essential anti -heamostatic enzymes (Decrem et al, 2007). Subsequent vaccination against these salivary gland metalloproteases did in fact affect the engorgement weight and fecundity of I. ricinus (with 47% and 55.4%, respectively) (Decrem et al, 2007) and the mortality of H. longicornis (with 14.6%) (Imamura et al, 2009). These reports support the notion that tick metzincin metalloproteases are promising anti-tick vaccine candidates and require further investigation to fully explore their potential.…”

Immunoprotective potential of a Rhipicephalus (Boophilus) microplus metalloprotease

“…Also, it was proposed that I. scapularis salivary MPs inhibits microvascular endothelial cell proliferation and degrades both ␣ and ␤ subunits of integrins ␣5␤1 and ␣1␤1 (Francischetti et al, 2005;Kazimirova and Stibraniova, 2013). Previous studies using H. longicornis MP as antigen demonstrated that nymph and adult tick mortality increases (Imamura et al, 2009). In I. ricinus, inhibition of MPs expression by RNAi prevents completion of tick blood meal and impairs tick saliva fibrinolytic and fibrinogenolytic activities (Decrem et al, 2008a(Decrem et al, , 2008b.…”

“…Host vaccination with an I. ricinus recombinant MP impairs blood meal completion, besides reducing tick weight gain and oviposition rates (Decrem et al, 2008b). In Haemaphysalis longicornis, six MPs were identified, one of which was shown to be a potentially interesting immunoprotective antigen (Harnnoi et al, 2007;Imamura et al, 2009).…”