The recombinant protein rSP03B is a valid antigen for screening dog exposure to Phlebotomus perniciosus across foci of canine leishmaniasis

Abstract

Abstract. The frequency of sandfly-host contacts can be measured by host antibody levels against sandfly salivary proteins. Recombinant salivary proteins are suggested to represent a valid replacement for salivary gland homogenate (SGH); however, it is necessary to prove that such antigens are recognized by antibodies against various populations of the same species. Phlebotomus perniciosus (Diptera: Psychodidae) is the main vector of Leishmania infantum (Trypanosomatida: Trypanosomatidae) in southwest Europe and is widespread from Portugal to Italy. In this study, sera were sampled from naturally exposed dogs from distant regions, including Campania (southern Italy), Umbria (central Italy) and the metropolitan Lisbon region (Portugal), where P. perniciosus is the unique or principal vector species. Sera were screened for anti-P. perniciosus antibodies using SGH and 43-kDa yellow-related recombinant protein (rSP03B). A robust correlation between antibodies recognizing SGH and rSP03B was detected in all regions, suggesting substantial antigenic cross-reactivity among different P. perniciosus populations. No significant differences in this relationship were detected between regions. Moreover, rSP03B and the native yellow-related protein were shown to share similar antigenic epitopes, as canine immunoglobulin G (IgG) binding to the native protein was inhibited by pre-incubation with the recombinant form. These findings suggest that rSP03B should be regarded as a universal marker of sandfly exposure throughout the geographical distribution of P. perniciosus.

Comparative Evolution of Sand Fly Salivary Protein Families and Implications for Biomarkers of Vector Exposure and Salivary Vaccine Candidates

“…longipalpis (Teixeira et al, 2010), Lu. intermedia (Carvalho et al, 2017), P. papatasi (Marzouki et al, 2015), P. perniciosus (Drahota et al, 2014; Kostalova et al, 2017), and P. orientalis (Sima et al, 2016). For the most part, the best salivary protein candidates belong to conserved protein families.…”

“…For the most part, the best salivary protein candidates belong to conserved protein families. Although the less conserved Silk protein (Figure 3) was found to be the best biomarker of P. papatasi exposure (Marzouki et al, 2015), members of the apyrase, ParSP25, and antigen-5 conserved families have been shown as good markers of exposure in P. perniciosus (Drahota et al, 2014; Kostalova et al, 2017), P. orientalis (Sima et al, 2016), and Lu. intermedia (Carvalho et al, 2017), respectively.…”

“…ParSP25 proteins were shown to work as biomarkers of vector exposure for P. perniciosus and P. orientalis (Drahota et al, 2014; Sima et al, 2016; Kostalova et al, 2017). Such a protein family was among the least divergent families unique to OW sand flies (Figures 2A,B) and was only expressed in member of the L/A/E subgenera (Table 1).…”

“…These findings have prompted research groups to explore the use of sand fly salivary proteins as markers of sand fly exposure for humans and animal reservoirs (Teixeira et al, 2010; Drahota et al, 2014; Marzouki et al, 2015; Sima et al, 2016; Kostalova et al, 2017). A recombinant sand fly salivary protein of 43 kDa (rSP03B), from the sand fly P. pernicious , belonging to the yellow family of proteins was shown to be a marker of sand fly exposure in dogs living in Southern and Central Italy and in Portugal (Drahota et al, 2014; Kostalova et al, 2017). Interestingly, the yellow related protein from P. orientalis (rPorSP24) was demonstrated to be a good marker of sand fly exposure in domestic animals including dogs from a L. donovani foci in Ethiopia (Sima et al, 2016).…”

Serological association between Leishmania infantum and sand fly fever Sicilian (but not Toscana) virus in sheltered dogs from southern Portugal

“…Thus, the aim of the present study was to investigate a possible association between exposure to Leishmania , TOSV and SFSV in sheltered dogs from Lisboa and Setúbal districts, south of Portugal, where the presence of the protozoan [23] and both phleboviruses [21] was previously reported.…”