Boophilus microplus: the pattern of bovine immunoglobulin isotype responses to high and low tick infestations.

Cattle present variable levels of resistance to ticks and the immune correlates of these heritable phenotypes must be known in order to develop effective vaccines. The antibody responses to tick salivary antigens were examined in cattle of tick-susceptible (Holstein) and tick-resistant (Nelore) breeds. After heavy infestations, levels of IgG1 and IgG2 antibodies decreased in Holsteins and remained the same in Nelores.