title: Haplotypes of the bovine IgG2 heavy gamma chain in tick-resistant and tick-susceptible breeds of cattle.
abstract: Bovines present contrasting, heritable phenotypes of infestations with the cattle tick, Rhipicephalus (Boophilus) microplus. Tick salivary glands produce IgG-binding proteins (IGBPs) as a mechanism for escaping from host antibodies that these ectoparasites ingest during blood meals. Allotypes that occur in the constant region of IgG may differ in their capacity to bind with tick IGBPs; this may be reflected by the distribution of distinct allotypes according to phenotypes of tick infestations. In order to test this hypothesis, we investigated the frequency of haplotypes of bovine IgG2 among tick-resistant and tick-susceptible breeds of bovines. Sequencing of the gene coding for the heavy chain of IgG2 from 114 tick-resistant (Bos taurus indicus, Nelore breed) and tick-susceptible (B. t. taurus, Holstein breed) bovines revealed SNPs that generated 13 different haplotypes, of which 11 were novel and 5 were exclusive of Holstein and 3 of Nelore breeds. Alignment and modeling of coded haplotypes for hinge regions of the bovine IgG2 showed that they differ in the distribution of polar and hydrophobic amino acids and in shape according to the distribution of these amino acids. We also found that there was an association between genotypes of the constant region of the IgG2 heavy chain with phenotypes of tick infestations. These findings open the possibility of investigating if certain IgG allotypes hinder the function of tick IGBPs. If so, they may be markers for breeding for resistance against tick infestations.
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP, Brazil.
authors.forename: Wanessa Araújo
authors.initials: WA
authors.lastname: Carvalho
authors.forename: Patricia
authors.initials: P
authors.lastname: Ianella
authors.forename: Frederico G C
authors.initials: FG
authors.lastname: Arnoldi
authors.forename: Alexandre Rodrigues
authors.initials: AR
authors.lastname: Caetano
authors.forename: Sandra Regina
authors.initials: SR
authors.lastname: Maruyama
authors.forename: Beatriz Rossetti
authors.initials: BR
authors.lastname: Ferreira
authors.forename: Luís Henrique Andreucci
authors.initials: LH
authors.lastname: Conti
authors.forename: Marcia Ramos Monteiro
authors.initials: MR
authors.lastname: da Silva
authors.forename: José Otavio F
authors.initials: JO
authors.lastname: Paula
authors.forename: Antonio Augusto Mendes
authors.initials: AA
authors.lastname: Maia
authors.forename: Isabel K Ferreira de Miranda
authors.initials: IK
authors.lastname: Santos
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle / Q000235:genetics* / Q000276:immunology; D002418:Cattle Diseases / Q000235:genetics* / Q000276:immunology / Q000469:parasitology; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007142:Immunoglobulin gamma-Chains / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide; D012469:Salivary Glands / Q000276:immunology; D013984:Tick Infestations / Q000235:genetics / Q000276:immunology / Q000662:veterinary*; D013987:Ticks / Q000276:immunology
chemical_list: D007143:Immunoglobulin Heavy Chains; D007142:Immunoglobulin gamma-Chains