Host Modification of Chlamydiae: Differential Infectivity for Cell Monolayers of Chlamydiae Grown in Eggs and Monolayers

Abstract

~Cell monolayer-grown chlamydiae (CGO) differed from egg-grown organisms (EGO) in their increased spontaneous infectivity relative to centrifuge-assisted infectivity for monolayers. For each population spontaneous : centrifuge-assisted infectivity ratios were constant Over a wide dose range. Spontaneous infection increased linearly with time and could not be exhausted from either population by prolonged adsorption; there was no change in infectivity ratios in residual supernatants. Further, one passage of EGO through monolayers gave CGO with stable infectivity properties not increased by further cell passage yet reverting on a single passage in eggs. Spontaneous infection of monolayers with EGO gave progeny with the same infectivity ratios as monolayers infected with EGO by centrifugation. The change in properties following EGO infection of monolayers occurred prior to natural release from cells. We conclude that EGO and CGO are two phenotypically distinct, homogeneous populations. The two infection modes are not properties of subpopulations within EGO and CGO. The relationship of these observations on chlamydiae to other possible host-imposed phenomena is considered.

Extensive heterogeneity of the protein composition of Chlamydia trachomatis following serial passage in two different cell lines

“…Acquisition of stable infectivity properties by a single passage of egg-grown Chlamydia psittaci GPIC in McCoy cell cultures was first noted by Allan & Pearce (1979a). After a single passage in cell culture, the progeny acquired enhanced ability to infect McCoy cells without centrifugal deposition of the bacteria onto the monolayer cultures.…”