Vaccination Response in Rabbits Related to Quantity of Vaccinia Virus Particles and Passage Level

Abstract
Summary: The antigenicity and immunizing potential of early and late L cell passage vaccinia virus were compared. Early passage virus produced a skin lesion in rabbits if as few as 200 VP were injected. Late passage virus produced no necrotic lesion in concentrations as high as 109 VP. Both early and late passage virus immunization gave skin immunity to challenge by early passage virus. Early passage virus stimulated high titers of neutralizing antibody; late passage virus produced lower antibody titers.