Anopheles salivary gland proteomes from major malaria vectors

Abstract

BackgroundAntibody responses against Anopheles salivary proteins can indicate individual exposure to bites of malaria vectors. The extent to which these salivary proteins are species-specific is not entirely resolved. Thus, a better knowledge of the diversity among salivary protein repertoires from various malaria vector species is necessary to select relevant genus-, subgenus- and/or species-specific salivary antigens. Such antigens could be used for quantitative (mosquito density) and qualitative (mosquito species) immunological evaluation of malaria vectors/host contact. In this study, salivary gland protein repertoires (sialomes) from several Anopheles species were compared using in silico analysis and proteomics. The antigenic diversity of salivary gland proteins among different Anopheles species was also examined.ResultsIn silico analysis of secreted salivary gland protein sequences retrieved from an NCBInr database of six Anopheles species belonging to the Cellia subgenus (An. gambiae, An. arabiensis, An. stephensi and An. funestus) and Nyssorhynchus subgenus (An. albimanus and An. darlingi) displayed a higher degree of similarity compared to salivary proteins from closely related Anopheles species. Additionally, computational hierarchical clustering allowed identification of genus-, subgenus- and species-specific salivary proteins. Proteomic and immunoblot analyses performed on salivary gland extracts from four Anopheles species (An. gambiae, An. arabiensis, An. stephensi and An. albimanus) indicated that heterogeneity of the salivary proteome and antigenic proteins was lower among closely related anopheline species and increased with phylogenetic distance.ConclusionThis is the first report on the diversity of the salivary protein repertoire among species from the Anopheles genus at the protein level. This work demonstrates that a molecular diversity is exhibited among salivary proteins from closely related species despite their common pharmacological activities. The involvement of these proteins as antigenic candidates for genus-, subgenus- or species-specific immunological evaluation of individual exposure to Anopheles bites is discussed.

Detection of immunogenic proteins from Anopheles sundaicussalivary glands in the human serum

“…The IgG response increases signifi cantly with the increase in Anopheles exposure, as evaluated using conventional entomological methods during the transmission season (10) . The results of a study conducted by Fontaine et al also demonstrated a positive correlation between the average IgG response to SGEs of Aedes caspius and Aedes caspius density, which was affected by changes in the season and the ecological environment (18) . The level of the IgG response increased signifi cantly during peak exposure to Ae.…”

“…This result may be explained by the presence of several proteins in the salivary glands of Anopheles that are conserved at the genus level (7) . Some proteins families are found in all Anopheles species; these are called genus-specifi c anopheline secreted proteins and include apyrase/5′ nucleotidase, antigen 5/gvag, GE-rich/30kDa, long and short form D7, mucin/13.5kDa, SG3, SG7, SG10, and hypothetical 6.2-kDa protein families (18) . Potential proteins having molecular weights of 61-63kDa include apyrase/5′ nucleotidase, which is involved in the blood feeding process through degradation (hydrolysis) of adenosine diphosphate (ADP) and adenosine triphosphate (ATP) to adenosine monophosphate (AMP), a mediator of platelet aggregation, infl ammation, and neutrophil activation (5) (22 (23) .…”

“…Many studies have been conducted to identify and characterize immunogenic salivary proteins from malaria vectors in Africa; however, malaria vectors in Asia, particularly An. sundaicus, have not been studied (8) (17) (18) .…”

Purification of Plasmodium Sporozoites Enhances Parasite-Specific CD8 + T Cell Responses

“…Of interest here, Anopheles antigens are known humoral immune targets; antibody titers against mosquito salivary gland extracts are even indicative of mosquito biting intensity (18). Constituent salivary gland proteins are increasingly well identified (19), and some proteins, such as salivary gland protein-4 and -5, are known antibody targets (20). Aside from humoral immunity, A. stephensi bites also activate mast cells and contribute to T cell hyperplasia in lymph nodes (21).…”

Efficient ΦC31 integrase–mediated site-specific germline transformation of Anopheles gambiae

“…gambiae genome sequence in 2002 an abundance of proteomic, transcriptomic and genome wide association data have been produced to try to understand the intimate relationships between the mosquito and Plasmodium parasites with the aim of identifying rational new means to control malaria transmission [1][2][3][4][5] . Other features of Anopheles biology relevant to disease transmission have also been intensively studied, including mating behaviour, sex determination, olfactory response and insecticide resistance [6][7][8][9] .…”