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Saliva of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) inhibits classical and alternative complement pathways

BACKGROUND: Rhipicephalus (Boophilus) microplus is the main ectoparasite affecting livestock worldwide. For a successful parasitism, ticks need to evade several immune responses of their hosts, including the activation of the complement system. In spite of the importance of R. microplus, previous wo...

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Autores principales: Silva, Naylene C. S., Vale, Vladimir F., Franco, Paula F., Gontijo, Nelder F., Valenzuela, Jesus G., Pereira, Marcos H., Sant’Anna, Mauricio R. V., Rodrigues, Daniel S., Lima, Walter S., Fux, Blima, Araujo, Ricardo N.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4982215/
https://www.ncbi.nlm.nih.gov/pubmed/27515662
http://dx.doi.org/10.1186/s13071-016-1726-8
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author Silva, Naylene C. S.
Vale, Vladimir F.
Franco, Paula F.
Gontijo, Nelder F.
Valenzuela, Jesus G.
Pereira, Marcos H.
Sant’Anna, Mauricio R. V.
Rodrigues, Daniel S.
Lima, Walter S.
Fux, Blima
Araujo, Ricardo N.
author_facet Silva, Naylene C. S.
Vale, Vladimir F.
Franco, Paula F.
Gontijo, Nelder F.
Valenzuela, Jesus G.
Pereira, Marcos H.
Sant’Anna, Mauricio R. V.
Rodrigues, Daniel S.
Lima, Walter S.
Fux, Blima
Araujo, Ricardo N.
author_sort Silva, Naylene C. S.
collection PubMed
description BACKGROUND: Rhipicephalus (Boophilus) microplus is the main ectoparasite affecting livestock worldwide. For a successful parasitism, ticks need to evade several immune responses of their hosts, including the activation of the complement system. In spite of the importance of R. microplus, previous work only identified one salivary molecule that blocks the complement system. The current study describes complement inhibitory activities induced by R. microplus salivary components and mechanisms elicited by putative salivary proteins on both classical and alternative complement pathways. RESULTS: We found that R. microplus saliva from fully- and partially engorged females was able to inhibit both pathways. Saliva acts strongly at the initial steps of both complement activation pathways. In the classical pathway, the saliva blocked C4 cleavage, and hence, deposition of C4b on the activation surface, suggesting that the inhibition occurs at some point between C1q and C4. In the alternative pathway, saliva acts by binding to initial components of the cascade (C3b and properdin) thereby preventing the C3 convertase formation and reducing C3b production and deposition as well as cleavage of factor B. Saliva has no effect on formation or decay of the C6 to C8 components of the membrane attack complex. CONCLUSION: The saliva of R. microplus is able to inhibit the early steps of classical and alternative pathways of the complement system. Saliva acts by blocking C4 cleavage and deposition of C4b on the classical pathway activation surface and, in the alternative pathway, saliva bind to initial components of the cascade (C3b and properdin) thereby preventing the C3 convertase formation and the production and deposition of additional C3b. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-016-1726-8) contains supplementary material, which is available to authorized users.
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spelling pubmed-49822152016-08-13 Saliva of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) inhibits classical and alternative complement pathways Silva, Naylene C. S. Vale, Vladimir F. Franco, Paula F. Gontijo, Nelder F. Valenzuela, Jesus G. Pereira, Marcos H. Sant’Anna, Mauricio R. V. Rodrigues, Daniel S. Lima, Walter S. Fux, Blima Araujo, Ricardo N. Parasit Vectors Research BACKGROUND: Rhipicephalus (Boophilus) microplus is the main ectoparasite affecting livestock worldwide. For a successful parasitism, ticks need to evade several immune responses of their hosts, including the activation of the complement system. In spite of the importance of R. microplus, previous work only identified one salivary molecule that blocks the complement system. The current study describes complement inhibitory activities induced by R. microplus salivary components and mechanisms elicited by putative salivary proteins on both classical and alternative complement pathways. RESULTS: We found that R. microplus saliva from fully- and partially engorged females was able to inhibit both pathways. Saliva acts strongly at the initial steps of both complement activation pathways. In the classical pathway, the saliva blocked C4 cleavage, and hence, deposition of C4b on the activation surface, suggesting that the inhibition occurs at some point between C1q and C4. In the alternative pathway, saliva acts by binding to initial components of the cascade (C3b and properdin) thereby preventing the C3 convertase formation and reducing C3b production and deposition as well as cleavage of factor B. Saliva has no effect on formation or decay of the C6 to C8 components of the membrane attack complex. CONCLUSION: The saliva of R. microplus is able to inhibit the early steps of classical and alternative pathways of the complement system. Saliva acts by blocking C4 cleavage and deposition of C4b on the classical pathway activation surface and, in the alternative pathway, saliva bind to initial components of the cascade (C3b and properdin) thereby preventing the C3 convertase formation and the production and deposition of additional C3b. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-016-1726-8) contains supplementary material, which is available to authorized users. BioMed Central 2016-08-11 /pmc/articles/PMC4982215/ /pubmed/27515662 http://dx.doi.org/10.1186/s13071-016-1726-8 Text en © The Author(s). 2016 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Silva, Naylene C. S.
Vale, Vladimir F.
Franco, Paula F.
Gontijo, Nelder F.
Valenzuela, Jesus G.
Pereira, Marcos H.
Sant’Anna, Mauricio R. V.
Rodrigues, Daniel S.
Lima, Walter S.
Fux, Blima
Araujo, Ricardo N.
Saliva of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) inhibits classical and alternative complement pathways
title Saliva of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) inhibits classical and alternative complement pathways
title_full Saliva of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) inhibits classical and alternative complement pathways
title_fullStr Saliva of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) inhibits classical and alternative complement pathways
title_full_unstemmed Saliva of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) inhibits classical and alternative complement pathways
title_short Saliva of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) inhibits classical and alternative complement pathways
title_sort saliva of rhipicephalus (boophilus) microplus (acari: ixodidae) inhibits classical and alternative complement pathways
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4982215/
https://www.ncbi.nlm.nih.gov/pubmed/27515662
http://dx.doi.org/10.1186/s13071-016-1726-8
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