Effects of penicillin on the synthesis of membrane proteins of Chlamydia trachomatis LGV2 serotype

Abstract

Cultures of LLC‐MK2 cells were infected with Chlamydia trachomatis LGV2 serotype and incubated in medium containing 200 units per ml of penicillin. Forty‐eight hours after infection, cells were removed and chlamydiae purified. By Coomassie blue‐stained polyacrylamide gels, penicillin‐treated chlamydiae showed to be deficient in 60 K and 62 K outer membrane proteins. By using a more sensitive immunoblotting technique, in conjunction with human and animal immune sera containing antibodies specific for the 60 K and 62 K proteins, the synthesis of the 60 K protein turned out to be completely inhibited by penicillin, whereas the 62 K protein seemed to be unaffected. The synthesis of the major outer membrane protein (MOMP), studied with a specific monoclonal antibody by using immunofluorescence and immunoblotting techniques, did not seem affected by penicillin. These data indicate that penicillin interferes with conversion of reticulate body to elementary body of C. trachomatis LGV2 serotype, by affecting the synthesis of the 60 K cysteine‐rich outer membrane protein.

The effect of penicillin on Chlamydia trachomatis DNA replication

“…It has been reported that b-lactam antibiotic treatments cause repression of omcB gene expression (omcB encodes the cysteine rich 60 kDa outer-membrane protein) (Cevenini et al, 1988;Sardinia et al, 1988). To verify that penicillin treatment in our system was consistent with these observations, we followed the accumulation of the OmcB protein by ELISA using polyclonal antisera raised against C. trachomatis OmcB (Watson et al, 1994).…”

Chlamydial Persistence: beyond the Biphasic Paradigm

“…A well-known example is the 60-kDa cysteine-rich protein (CRP), which is abundant in EB envelopes. The 60-kDa CRP was either markedly diminished or completely absent in early studies of C. trachomatis strains exposed to ␤-lactam antibiotics (23,104), IFN-␥ (7, 10), or heat shock (53). Another study reported the absence of the Hc-1 and Hc-2 DNA-binding proteins (involved in chromosomal condensation) in IFN-␥-exposed C. trachomatis, although interestingly, the 60-kDa CRP was not down-regulated (52) ( Table 2).…”

Secretion of proinflammatory cytokines by epithelial cells in response to Chlamydia infection suggests a central role for epithelial cells in chlamydial pathogenesis.

“…Penicillin inhibits RB division and RB to EB differentiation, but has no known effect on RB metabolism (37,38). As shown in Fig.…”