title: Immune recognition of salivary proteins from the cattle tick Rhipicephalus microplus differs according to the genotype of the bovine host.
abstract: BACKGROUND
  Males of the cattle tick Rhipicephalus microplus produce salivary immunoglobulin-binding proteins and allotypic variations in IgG are associated with tick loads in bovines. These findings indicate that antibody responses may be essential to control tick infestations. Infestation loads with cattle ticks are heritable: some breeds carry high loads of reproductively successful ticks, in others, few ticks feed and they reproduce inefficiently. Different patterns of humoral immunity against tick salivary proteins may explain these phenotypes.
  
  
  METHODS
  We describe the profiles of humoral responses against tick salivary proteins elicited during repeated artificial infestations of bovines of a tick-resistant (Nelore) and a tick-susceptible (Holstein) breed. We measured serum levels of total IgG1, IgG2 and IgE immunoglobulins and of IgG1 and IgG2 antibodies specific for tick salivary proteins. With liquid chromatography followed by mass spectrometry we identified tick salivary proteins that were differentially recognized by serum antibodies from tick-resistant and tick-susceptible bovines in immunoblots of tick salivary proteins separated by two-dimensional electrophoresis.
  
  
  RESULTS
  Baseline levels of total IgG1 and IgG2 were significantly higher in tick-susceptible Holsteins compared with resistant Nelores. Significant increases in levels of total IgG1, but not of IgG2 accompanied successive infestations in both breeds. Resistant Nelores presented with significantly higher levels of salivary-specific antibodies before and at the first challenge with tick larvae; however, by the third challenge, tick-susceptible Holsteins presented with significantly higher levels of IgG1 and IgG2 tick salivary protein-specific antibodies. Importantly, sera from tick-resistant Nelores reacted with 39 tick salivary proteins in immunoblots of salivary proteins separated in two dimensions by electrophoresis versus only 21 spots reacting with sera from tick-susceptible Holsteins.
  
  
  CONCLUSIONS
  Levels of tick saliva-specific antibodies were not directly correlated with infestation phenotypes. However, in spite of receiving apparently lower amounts of tick saliva, tick-resistant bovines recognized more tick salivary proteins. These reactive salivary proteins are putatively involved in several functions of parasitism and blood-feeding. Our results indicate that neutralization by host antibodies of tick salivary proteins involved in parasitism is essential to control tick infestations.
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Gustavo Rocha
authors.initials: GR
authors.lastname: Garcia
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Sandra Regina
authors.initials: SR
authors.lastname: Maruyama
authors.affiliation: Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA, USA.
authors.forename: Kristina T
authors.initials: KT
authors.lastname: Nelson
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
authors.forename: José Marcos Chaves
authors.initials: JM
authors.lastname: Ribeiro
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Luiz Gustavo
authors.initials: LG
authors.lastname: Gardinassi
authors.affiliation: Department of Basic Sciences, School of Animal Science and Food Technology, University of São Paulo, Pirassununga, São Paulo, Brazil.
authors.forename: Antonio Augusto Mendes
authors.initials: AA
authors.lastname: Maia
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.|Department of Maternal-Child Nursing and Public Health, Ribeirão Preto School of Nursing, USP, Ribeirão Preto, SP, Brazil.
authors.forename: Beatriz Rossetti
authors.initials: BR
authors.lastname: Ferreira
authors.affiliation: Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Frans N J
authors.initials: FN
authors.lastname: Kooyman
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil. imsantos@fmrp.usp.br.
authors.forename: Isabel K F
authors.initials: IK
authors.lastname: de Miranda Santos
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000276:immunology*; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000235:genetics* / Q000276:immunology*; D005260:Female; D005838:Genotype; D008297:Male; D048494:Rhipicephalus / Q000235:genetics / Q000276:immunology*; D012471:Salivary Proteins and Peptides / Q000276:immunology*; D013984:Tick Infestations / Q000235:genetics / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*
chemical_list: D060829:Arthropod Proteins; D012471:Salivary Proteins and Peptides
keywords: Antibody response; Bos indicus; Bos taurus; Immunoglobulins; Immunoproteome; Proteome; Rhipicephalus microplus; Tick saliva