A proteomics approach for the analysis of hemolymph proteins involved in the immediate defense response of the soft tick, Ornithodoros savignyi, when challenged with Candida albicans

Abstract

A proteomics approach was employed to identify proteins secreted into the hemolymph of O. savignyi ticks two hours after immune-challenge with the yeast, Candida albicans. Profiling of the proteins present in hemolymph of unchallenged ticks versus ticks challenged with heat-killed yeast revealed 5 proteins to be differentially expressed. The modulated protein spots were subjected to tandem mass spectrometry (MS/MS) analysis, but could not be positively identified. These proteins can be assigned to the immune response as they were not induced after aseptic injury. In an attempt to identify hemolymph proteins that recognize and bind to yeast cells, hemolymph obtained from both unchallenged and challenged ticks was incubated with C. albicans. Elution of the bound proteins followed by SDS-PAGE analysis indicated that three proteins (97, 88 and 26 kDa) present in both unchallenged and challenged hemolymph samples bind to yeast cells. The constant presence of these three proteins in tick hemolymph leads us to believe that they may be involved in non-self recognition and participate in yeast clearance from tick plasma. The analyzed yeast-binding proteins could also not be positively identified, suggesting that all the tick immune proteins investigated in this study are novel.

Application of highly sensitive saturation labeling to the analysis of differential protein expression in infected ticks from limited samples

“…Due to complexities of working with ticks and despite great advances in proteomics technologies during the last decades, proteomics studies to characterize protein expression in ticks are difficult to conduct [5-17]. Most of these studies have focused on the sialome (salivary gland secretory proteome) analysis of ticks [6,7,9,13-15] and the analysis of host-tick-pathogen interactions in an attempt to identify potential candidates for vaccine development against vector-borne diseases [5,8,10-12,16,17].…”

Update on the proteomics of major arthropod vectors of human and animal pathogens

“…Another differential proteomic analysis addressed systemic innate immunity in tick hemolymph. After immunization of the soft tick Ornithodoros savignyi with Candida albicans, five proteins in the hemolymph were specifically regulated by the yeast but they could not be definitively identified [40] although they may be involved in yeast clearance. This illustrates how the fact that the number of sequences available in databases is limited is hindering the identification of tick proteins using proteomic approaches.…”

Protein profiling of hemolymph in Haemaphysalis flava ticks

“…Nevertheless, thus far there have been only two reports describing the protein profile in tick hemolymph. Stopforth et al conducted a proteomic study to identify proteins secreted in the hemolymph of Ornithodoros savignyi ticks following immune challenge with yeasts [ 22 ]. Aguilar-Díaz et al compared hemolymph proteomes of two R. microplus strains with different degrees of resistance to ixodicides [ 23 ].…”