Kinetics of Canine Antibody Response to Saliva of the Sand Fly Lutzomyia longipalpis

Abstract

Zoonotic visceral leishmaniasis (VL) caused by Leishmania infantum is transmitted from dogs to humans by sand flies and Lutzomyia longipalpis is a major vector of this disease. We studied the antibody response in dogs experimentally exposed to L. longipalpis females to characterize sand fly salivary antigens recognized by canine sera and to find out whether the level of specific anti-saliva antibodies reflects the intensity of exposure. Sera from repeatedly bitten dogs revealed up to six salivary protein bands with approximate molecular weight of 66, 55, 45, 37-39, 34, and 25 kDa in L. longipalpis salivary gland lysate. Anti-saliva immunoglobin (Ig) G and its subclasses were found to be useful markers of exposure to sand flies. Specific IgG, IgG1, and IgG2 were related to numbers of bloodfed L. longipalpis females, and increased antibody levels were detectable throughout the study, i.e. more than 6 months after the last exposure. In contrast, specific IgE response developed in some dogs only, and no correlation was observed between its level and the intensity of exposure. Screening of dog sera for specific IgG against salivary antigens of the vector is suggested as a useful epidemiological tool in VL foci. Monitoring canine antibody response to sand fly saliva also allows evaluation of the effectiveness of anti-vector campaigns.

Insights into the sand fly saliva: Blood-feeding and immune interactions between sand flies, hosts, and Leishmania

“…longipalpis . However, only IgG (and IgG2 subclass) correlated with sand fly exposure intensity [118, 119]. Anti-saliva IgG and IgG2 were observed also in sera from dogs exposed to P .…”

“…There are several studies focusing on the long-term kinetics of anti-saliva antibodies in mice [116, 117], dogs [118, 120], humans [122, 125], or rabbits [117]. In humans repeatedly bitten by P .…”

“…longipalpis and P . papatasi , respectively [116, 118]. However, a rapid antibody decrease in canine sera was observed within 1 week after the last P .…”

Canine antibody response to Lutzomyia longipalpis saliva in endemic area of visceral leishmaniasis.

“…The saliva induces antibody production in repeatedly bitten hosts that are highly specific to the sand fly species Lu. longipalpis, and the antibody level reflects the intensity of vector exposure (6) . Therefore, antibodies against sand fly saliva have been used in epidemiological studies as an exposure marker to the vector bite, as well as to estimate the likely risk of Leishmania transmission (7) .…”

Phlebotomus papatasi exposure cross-protects mice against Leishmania major co-inoculated with Phlebotomus duboscqi salivary gland homogenate

“…While antisaliva antibody response correlates with the intensity of exposure (Hostomska et al, 2008;Vlkova et al, 2011;Vlkova et al, 2012) and can be used as a reliable epidemiological tool (e.g. Clements et al, 2010;Gidwani et al, 2011), specific cellular immunity, particularly the delayed type hypersensitive reaction (DTH), is responsible for protection against leishmaniasis (Gomes et al, 2008;Kamhawi et al, 2000;Valenzuela et al, 2001).…”