Attachment & entry of C. trachomatis E

[The cell biology work of Pris Wyrick, Jane Raulston and their colleagues is distinguished by their use of a hormone-sensitive, endometrial carcinoma cell line, HEC-1B, which has a polarised orientation similar to uroepithelial cells. While charged molecules like DEAE dextran, poly-L-lysine and heparan sulphate have long been known to inhibit the attachment and entry of the LGV biovar of C. trachomatis, [See: attachment], it is clear that the TRIC biovar of C. trachomatis responsible for the vast majority of ocular and genital infections in humans is much less susceptible to inhibition by these molecules, suggesting that there are different receptor mechanisms. The important role of oestrogen and progesterone on the attachment and entry of C. trachomatis in uroepithelial cells is also not understood.  At the International Chlamydia Conference in June 2002, preliminary evidence was presented that a component of the host cell oestrogen receptor, protein disulphide isomerase, may be involved in the infectivity of TRIC isolates. The original presentation has kindly been made available on Chlamydiae.com and a full paper has been published: Davis et al., 2002].

[MEW November 2002]

Presentation by Wyrick, Raulston & Davis, June 2002:

Fig 1. Title. These figures © Wyrick, Raulston & Davis, 2002 modified from presentation at Antalya June 2002	Fig 2. Proposed adhesins and epithelial receptors for the chlamydiae.	Fig 3. Experimental methodology. The apical membranes of polarized HEC-1B cells were biotinylated prior to attachment of EB. Poly-L-lysine coated glass coverslips were pressed onto the apical surface, resulting in transfer of EB + membrane. Latter solubilised with NP40 then immunoprecipitated with EB antibody and biotinylated receptors detected on blots with neutravidin.	Fig 4. A) A unique 55 KDa membrane protein co-precipitated with EB. B) Protein identified as Protein disulphide isomerase by 2D electrophoresis and MALDI. C) That this was PDI was confirmed by Western Blot with PDI antiserum.
Fig 5. Properties of protein disulphide isomerase & inhibitors of PDI mediated reduction used for subsequent experiments.	Fig 6. Chlamydial infectivity was reduced 30% by the thiol-alkylating agent DNTB @ 4C; 27-36% by bacitracin at 35C and 62-69% by anti PDI McAb.	Fig 7. PDI is associated with oestrogen but not progesterone receptor function.	Fig 8.C. trachomatis has two PDI genes but these are not closely homologous to eukaryotic (ie host) PDI.
Fig 9. Hypothesis: Possible role of eukaryotic PDI in promoting chlamydial entry.	Fig 10. Associated evidence suggesting that PDI may be involved with chlamydial entry.

[PW]

Reference