Role of IgG allotypes in bovine resistance to ticks and their interaction with the IgG-binding protein (IGBP-C) from the saliva of the tick Riphicephalus microplus

• Grant number: 12/11372-3
• Support Opportunities: Scholarships in Brazil - Master
• Start date: August 01, 2012
• End date: January 31, 2014
• Field of knowledge: Biological Sciences - Immunology - Immunogenetics
• Principal Investigator: Isabel Kinney Ferreira de Miranda Santos
• Grantee: Amanda Fonseca Zangirolamo
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Rhipicephalus microplus is the most important ectoparasite of livestock and the main constraint for the advancement of cattle production. It causes huge economic losses. Acaricides are the current method of control, but ticks are developing alarming levels of resistance to them; furthermore acaricides contaminate milk, beef and the environment. During infestations large quantities of immunoglobulins are ingested by ticks together with blood. Consequently male ticks assist the female to escape this host immune response by making large quantities of salivary IgG-binding proteins (IGBPs), which theoretically interferes in the functions of IgG such as complement activation and binding to Fc receptors. Different breeds of bovines present different frequencies of variations of the constant region of IgG, i.e., allotypes and also different levels of infestations with R. microplus. It has been well established that different IgG allotypes bind differentially to IGBPs of various pathogens and to complement and Fc receptors. In view of these phenomena, the present work aims to evaluate the nature of the interactions between the IGBP-C of R. microplus and the allotypes of bovine IgGs with the objective of developing new strategies for the control of this important ectoparasite.