Haplotypes of the bovine IgG2 heavy gamma chain in tick-resistant and tick-susceptible breeds of cattle

Author(s):Show less -

Carvalho, Wanessa Araujo ^[1] ; Ianella, Patricia ^[2] ; Arnoldi, Frederico G. C. ^[1] ; Caetano, Alexandre Rodrigues ^[2] ; Maruyama, Sandra Regina ^[1] ; Ferreira, Beatriz Rossetti ^[3] ; Andreucci Conti, Luis Henrique ^[4] ; Monteiro da Silva, Marcia Ramos ^[4] ; Paula, Jose Otavio F. ^[4] ; Mendes Maia, Antonio Augusto ^[4] ; Ferreira de Miranda Santos, Isabel K. ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Ribeirao Preto Sch Med, Dept Biochem & Immunol, BR-14049900 Ribeirao Preto, SP - Brazil

^[2] Brazilian Enterprise Agr Res, Ctr Genet Resources & Biotechnol, BR-70770900 Brasilia, DF - Brazil

^[3] Univ Sao Paulo, Ribeirao Preto Sch Nursing, Dept Maternal & Child Nursing & Publ Hlth, BR-14049900 Ribeirao Preto, SP - Brazil

^[4] Univ Sao Paulo, Fac Anim Sci & Food Engn, Dept Basic Sci, BR-13635900 Pirassununga, SP - Brazil

• Document type: Journal article
• Source: IMMUNOGENETICS; v. 63, n. 5, p. 319-324, MAY 2011.
• Web of Science Citations: 8

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. (AU)