The immune response of rabbits to 3 strains of Mycoplasma agalactiae var. bovis isolated from mastitic bovine udders

Rabbits were given 3 serologically-related trains of mycoplasma isolated from mastitic bovine udders. Growth inhibiting antibodies were not found. High-titered sera from each rabbit immunized with each strain developed at least 4 precipitin lines to each organism and at least one line of identity was demonstrated between the organisms. Significant indirect hemagglutination titers were found in all rabbits in 1 week, with titers reaching 1.0 X 10(5) to 3.3 X 10(5) in 4 to 6 weeks but despite continued intravenous antigenic stimulation, titers quickly fell to low levels thereafter.