Immunogenicity of recombinant Babesia microti hsp70 homologue in mice.

A Babesia microti hsp70 homologue was cloned, expressed in a prokaryotic system and tested in a pilot study for protection against lethal challenge. Results showed that 30% of the mice inoculated with recombinant protein (rBm hsp70) survived challenge, while all of the controls died. Evidence of antibody response to the hsp homologue was detected by Western blot analysis, but no protection was imparted through passive transfer of convalescent serum. Passively transferred spleen cells, from mice which survived challenge, also failed to impart protection. The mechanism of partial immunity suggested by these observations remains to be elucidated.