Serological response of the Mongolian gerbil to Babesia divergens (human strain) infection

Abstract

Sensitive serological assay systems were developed to measure the antibody responses in gerbils infected with a syringe-passaged human strain of Babesia divergens. High antibody titres were recorded by a triple-layered immunofluorescence assay. An improved ELISA technique, with sucrose gradient-purified parasites as antigen, proved to be almost as sensitive for the detection of specific antibody and correlated well with the immunofluorescence assay. Some gerbil sera with high immunofluorescence and ELISA values agglutinated B. divergens-infected gerbil erythrocytes at room temperature.

Antibody was apparently only protective when animals were ‘immunized’ with inert Babesia antigen, either prior to, or—in the case of some stabilates—concurrently with, infection with intact viable parasites. Only minimal serological cross-reaction was seen between the piro-plasms B. divergens and B. musculi in infected gerbils.