Differential neutralization of spontaneous and centrifuge-assisted chlamydial infectivity

Neutralization by specific antibody of a fast-killing variant strain of Chlamydia trachomatis, which showed high spontaneous infectivity for cell monolayers, was examined. It appeared that in spontaneous infection antibody-treated chlamydiae were neutralized by inhibition of attachment to cells. Centrifugation imposed a different effect: infection was inhibited at some step at or subsequent to attachment.