Cell-mediated immune response in hamsters infected with Babesia microti

Abstract A study was made of the cell-mediated immune (CMI) response in hamsters infected with Babesia microti isolated from a woman with clinical babesiosis. The leukocyte migration inhibition test (LMIT) using spleen leukocytes exposed to a soluble B. microti antigen was used for in vitro measurement of cellular immunity. The earliest detectable response was noted at the end of the second week after infection and persisted at relatively high levels throughout the 41-week observation period. Challenge infection caused a transitory but strong rise in the LMIT results. No hematologic manifestations of babesiosis were related to the challenge inoculation. The CMI responses were compared wiht humoral antibody measurements using the indirect fluorescent antibody (IFA) test.