Efficacy of a bacterin prepared from Chlamydia psittaci grown in cell culture for experimental immunization of ewes.

The efficacy of a bacterin prepared from Chlamydia psittaci grown in mouse L-cells was compared to a similar bacterin prepared from C. psittaci grown in chicken embryos (CE). Both bacterins significantly reduced (P less than 0.03) incidence of abortion and weak lambs compared to non-vaccinated control ewes. The L-cell bacterin elicited a greater antibody response than the CE bacterin (P less than 0.03).