Association of PPLO infection and antibody response in rats and mice

Abstract

By means of a complement-fixation test of the sera of laboratory rats and mice, the immunological response of these animals to both naturally occurring and induced PPLO infections was determined, and the presence and extent of infection in the animals determined by culture.PPLO antibodies specific for the infecting strain were demonstrable in rats and mice from which PPLO were isolated.The amount of serum antibody rises with the extent and severity of the infection. Thus, young rats with PPLO infections confined to the nasopharynx had little or no antibody whereas the oldest rats with consolidated lungs had the highest titres. In mice too, the sera of those with pneumonia had the highest titres.The comparatively low titres found in rat bronchiectasis together with the failure to isolate PPLO from the spleen and other organs, suggest that the chronic form of the disease remains localized. This is in contrast to infections with rat polyarthritis and related PPLO in which the organisms can be isolated from the lymph nodes and other organs and in which antibody is present in high titre.In view of the high degree of correlation between the presence of antibodies to PPLO in the blood and the presence of PPLO in the tissue of rats and mice, it is suggested that specific antibody found in man is a significant indicator of PPLO infection.