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Characterization of guinea pig antibody responses to salivary proteins of Triatoma infestans for the development of a triatomine exposure marker.

Dorňáková V, Salazar-Sanchez R, Borrini-Mayori K, Carrion-Navarro O, Levy MZ, Schaub GA, Schwarz A - PLoS Negl Trop Dis (2014)

Bottom Line: Salivary proteins of Triatoma infestans elicit humoral immune responses in their vertebrate hosts.In SDS-PAGE analysis of salivary proteins of T. infestans the banding pattern differed between developmental stages and strains of triatomines.Phenograms constructed from the salivary profiles separated nymphal instars, especially the 5th instar, from adults.

View Article: PubMed Central - PubMed

Affiliation: Institute of Parasitology, Biology Centre of the Academy of Sciences of Czech Republic, Ceske Budejovice, Czech Republic; Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic.

ABSTRACT

Background: Salivary proteins of Triatoma infestans elicit humoral immune responses in their vertebrate hosts. These immune responses indicate exposure to triatomines and thus can be a useful epidemiological tool to estimate triatomine infestation. In the present study, we analyzed antibody responses of guinea pigs to salivary antigens of different developmental stages of four T. infestans strains originating from domestic and/or peridomestic habitats in Argentina, Bolivia, Chile and Peru. We aimed to identify developmental stage- and strain-specific salivary antigens as potential markers of T. infestans exposure.

Methodology and principal findings: In SDS-PAGE analysis of salivary proteins of T. infestans the banding pattern differed between developmental stages and strains of triatomines. Phenograms constructed from the salivary profiles separated nymphal instars, especially the 5th instar, from adults. To analyze the influence of stage- and strain-specific differences in T. infestans saliva on the antibody response of guinea pigs, twenty-one guinea pigs were exposed to 5th instar nymphs and/or adults of different T. infestans strains. Western blot analyses using sera of exposed guinea pigs revealed stage- and strain-specific variations in the humoral response of animals. In total, 27 and 17 different salivary proteins reacted with guinea pig sera using IgG and IgM antibodies, respectively. Despite all variations of recognized salivary antigens, an antigen of 35 kDa reacted with sera of almost all challenged guinea pigs.

Conclusion: Salivary antigens are increasingly considered as an epidemiological tool to measure exposure to hematophagous arthropods, but developmental stage- and strain-specific variations in the saliva composition and the respective differences of immunogenicity are often neglected. Thus, the development of a triatomine exposure marker for surveillance studies after triatomine control campaigns requires detailed investigations. Our study resulted in the identification of a potential antigen as useful marker of T. infestans exposure.

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IgG antibody response of guinea pigs to saliva of nymphal and adult T. infestans of four different strains.(A) Eighteen guinea pigs were either exposed to the 5th instar (n = 5, white squares) or adults (n = 5, colored squares) of three different T. infestans strains from Argentina (blue line), Bolivia (red line) and Chile (green line). Each group of animals was made of 3 guinea pigs. Additionally, three guinea pigs were exposed to a set of nymphs (n = 10, white squares) and adult triatomines (n = 10, grey squares) from Peru (grey lines). Guinea pigs were exposed weekly to triatomines and for a period of 10 weeks. Animals were bled 5 days after each exposure and all sera were analyzed by ELISA using either crude saliva of nymphs or adults. From each group of guinea pig sera (n = 3) the mean optical density (O.D.490 nm) was calculated after subtracting the O.D. of the negative control (pre-exposure). The results here presented show the final mean optical densities (O.D.490 nm) of two independent ELISA assays. (B–E) Logistic models describing the relationship between the sum of feeding nymphal and/or adult triatomines (number of triatomines used at each feeding event plus the number of triatomines already fed in previous events) and the corresponding IgG antibody level of guinea pigs to saliva of the Peruvian (B, D), Argentinean (C, E, black graphs), Bolivian (C, E, blue graphs) and Chilean T. infestans strains (C, E, green graphs).
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pntd-0002783-g003: IgG antibody response of guinea pigs to saliva of nymphal and adult T. infestans of four different strains.(A) Eighteen guinea pigs were either exposed to the 5th instar (n = 5, white squares) or adults (n = 5, colored squares) of three different T. infestans strains from Argentina (blue line), Bolivia (red line) and Chile (green line). Each group of animals was made of 3 guinea pigs. Additionally, three guinea pigs were exposed to a set of nymphs (n = 10, white squares) and adult triatomines (n = 10, grey squares) from Peru (grey lines). Guinea pigs were exposed weekly to triatomines and for a period of 10 weeks. Animals were bled 5 days after each exposure and all sera were analyzed by ELISA using either crude saliva of nymphs or adults. From each group of guinea pig sera (n = 3) the mean optical density (O.D.490 nm) was calculated after subtracting the O.D. of the negative control (pre-exposure). The results here presented show the final mean optical densities (O.D.490 nm) of two independent ELISA assays. (B–E) Logistic models describing the relationship between the sum of feeding nymphal and/or adult triatomines (number of triatomines used at each feeding event plus the number of triatomines already fed in previous events) and the corresponding IgG antibody level of guinea pigs to saliva of the Peruvian (B, D), Argentinean (C, E, black graphs), Bolivian (C, E, blue graphs) and Chilean T. infestans strains (C, E, green graphs).

Mentions: The level of IgG antibodies increased in guinea pigs bitten by nymphal and/or adult triatomines from Argentina, Bolivia, Chile and Peru with serial exposures to T. infestans (Figure 3A). Anti-saliva IgG antibodies of guinea pigs exposed to the Peruvian T. infestans strain were detectable after the first exposure, although at a very low level (mean O.D. 490 nm = 0.003, Figure 3A). All other IgG antibody levels were detectable after the second exposure, at which some antibody levels were also very low (mean O.D. 490 nm range = 0.003–0.016). The highest antibody levels were reached in guinea pigs exposed to the Peruvian strain (mean max. O.D. 490 nm = 2.073).


Characterization of guinea pig antibody responses to salivary proteins of Triatoma infestans for the development of a triatomine exposure marker.

Dorňáková V, Salazar-Sanchez R, Borrini-Mayori K, Carrion-Navarro O, Levy MZ, Schaub GA, Schwarz A - PLoS Negl Trop Dis (2014)

IgG antibody response of guinea pigs to saliva of nymphal and adult T. infestans of four different strains.(A) Eighteen guinea pigs were either exposed to the 5th instar (n = 5, white squares) or adults (n = 5, colored squares) of three different T. infestans strains from Argentina (blue line), Bolivia (red line) and Chile (green line). Each group of animals was made of 3 guinea pigs. Additionally, three guinea pigs were exposed to a set of nymphs (n = 10, white squares) and adult triatomines (n = 10, grey squares) from Peru (grey lines). Guinea pigs were exposed weekly to triatomines and for a period of 10 weeks. Animals were bled 5 days after each exposure and all sera were analyzed by ELISA using either crude saliva of nymphs or adults. From each group of guinea pig sera (n = 3) the mean optical density (O.D.490 nm) was calculated after subtracting the O.D. of the negative control (pre-exposure). The results here presented show the final mean optical densities (O.D.490 nm) of two independent ELISA assays. (B–E) Logistic models describing the relationship between the sum of feeding nymphal and/or adult triatomines (number of triatomines used at each feeding event plus the number of triatomines already fed in previous events) and the corresponding IgG antibody level of guinea pigs to saliva of the Peruvian (B, D), Argentinean (C, E, black graphs), Bolivian (C, E, blue graphs) and Chilean T. infestans strains (C, E, green graphs).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3974673&req=5

pntd-0002783-g003: IgG antibody response of guinea pigs to saliva of nymphal and adult T. infestans of four different strains.(A) Eighteen guinea pigs were either exposed to the 5th instar (n = 5, white squares) or adults (n = 5, colored squares) of three different T. infestans strains from Argentina (blue line), Bolivia (red line) and Chile (green line). Each group of animals was made of 3 guinea pigs. Additionally, three guinea pigs were exposed to a set of nymphs (n = 10, white squares) and adult triatomines (n = 10, grey squares) from Peru (grey lines). Guinea pigs were exposed weekly to triatomines and for a period of 10 weeks. Animals were bled 5 days after each exposure and all sera were analyzed by ELISA using either crude saliva of nymphs or adults. From each group of guinea pig sera (n = 3) the mean optical density (O.D.490 nm) was calculated after subtracting the O.D. of the negative control (pre-exposure). The results here presented show the final mean optical densities (O.D.490 nm) of two independent ELISA assays. (B–E) Logistic models describing the relationship between the sum of feeding nymphal and/or adult triatomines (number of triatomines used at each feeding event plus the number of triatomines already fed in previous events) and the corresponding IgG antibody level of guinea pigs to saliva of the Peruvian (B, D), Argentinean (C, E, black graphs), Bolivian (C, E, blue graphs) and Chilean T. infestans strains (C, E, green graphs).
Mentions: The level of IgG antibodies increased in guinea pigs bitten by nymphal and/or adult triatomines from Argentina, Bolivia, Chile and Peru with serial exposures to T. infestans (Figure 3A). Anti-saliva IgG antibodies of guinea pigs exposed to the Peruvian T. infestans strain were detectable after the first exposure, although at a very low level (mean O.D. 490 nm = 0.003, Figure 3A). All other IgG antibody levels were detectable after the second exposure, at which some antibody levels were also very low (mean O.D. 490 nm range = 0.003–0.016). The highest antibody levels were reached in guinea pigs exposed to the Peruvian strain (mean max. O.D. 490 nm = 2.073).

Bottom Line: Salivary proteins of Triatoma infestans elicit humoral immune responses in their vertebrate hosts.In SDS-PAGE analysis of salivary proteins of T. infestans the banding pattern differed between developmental stages and strains of triatomines.Phenograms constructed from the salivary profiles separated nymphal instars, especially the 5th instar, from adults.

View Article: PubMed Central - PubMed

Affiliation: Institute of Parasitology, Biology Centre of the Academy of Sciences of Czech Republic, Ceske Budejovice, Czech Republic; Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic.

ABSTRACT

Background: Salivary proteins of Triatoma infestans elicit humoral immune responses in their vertebrate hosts. These immune responses indicate exposure to triatomines and thus can be a useful epidemiological tool to estimate triatomine infestation. In the present study, we analyzed antibody responses of guinea pigs to salivary antigens of different developmental stages of four T. infestans strains originating from domestic and/or peridomestic habitats in Argentina, Bolivia, Chile and Peru. We aimed to identify developmental stage- and strain-specific salivary antigens as potential markers of T. infestans exposure.

Methodology and principal findings: In SDS-PAGE analysis of salivary proteins of T. infestans the banding pattern differed between developmental stages and strains of triatomines. Phenograms constructed from the salivary profiles separated nymphal instars, especially the 5th instar, from adults. To analyze the influence of stage- and strain-specific differences in T. infestans saliva on the antibody response of guinea pigs, twenty-one guinea pigs were exposed to 5th instar nymphs and/or adults of different T. infestans strains. Western blot analyses using sera of exposed guinea pigs revealed stage- and strain-specific variations in the humoral response of animals. In total, 27 and 17 different salivary proteins reacted with guinea pig sera using IgG and IgM antibodies, respectively. Despite all variations of recognized salivary antigens, an antigen of 35 kDa reacted with sera of almost all challenged guinea pigs.

Conclusion: Salivary antigens are increasingly considered as an epidemiological tool to measure exposure to hematophagous arthropods, but developmental stage- and strain-specific variations in the saliva composition and the respective differences of immunogenicity are often neglected. Thus, the development of a triatomine exposure marker for surveillance studies after triatomine control campaigns requires detailed investigations. Our study resulted in the identification of a potential antigen as useful marker of T. infestans exposure.

Show MeSH
Related in: MedlinePlus