Immune system protein may help fight chlamydia

Researchers say a new understanding of the life cycle of chlamydia bacteria may help identify a better target for treatment.

By Stephen Feller

MOSCOW, July 28 (UPI) -- Proteins in the immune system can target the bacteria that cause chlamydia, but are not strong enough on their own to clear the infections, researchers found in a recent study.

The immune system is capable of mounting a defense against chlamydia infection, researchers in Russia found in a recent study, suggesting it could be harnessed for more effective treatment of the sexually transmitted infection.


Chlamydia bacteria occur in two forms, an elementary body with strong protection that allows it to move between cells, spread and infect new cells, while reticulate bodies exist inside host cells changing shape and size for reproduction. The more complex life cycle helps it to avoid antibacterial proteins.

Researchers at the Moscow Institute of Physics and Technology sought to test whether proteins in the immune system that can attach to peptidoglycan, a membrane component in bacteria such as E. coli and Bacillus subtilis, can also attach to Chlamydia trachomatis. Their expectation is the immune protein could overwhelm and disrupt bacterial cellular metabolism to kill chlamydia.

For the study, published in the journal Infection and Immunity, the researchers added peptidoglycan recognition proteins to cell cultures, infecting the cells with chlamydia.


After 48 hours, the researchers found peptidoglycan recognition proteins stopped the infection, reporting the number of infected cells was ten times less than in cultures without peptidoglycan recognition proteins. To do so, however, required a concentration of peptidoglycan recognition proteins about 20 times greater than levels that clear E. coli and B. subtilis.

The researchers also found the greatest effect of peptidoglycan recognition proteins on chlamydia was at 1 hour and 72 hours after infection, suggesting the life cycle of the bacteria has particularly vulnerable periods, according to the study.

"The findings of this research can subsequently be used to determine the exact mechanism of action of peptidoglycan-recognition proteins on chlamydias," Pavel Bobrovsky, a researcher at the Federal Research and Clinical Center of Physical-Chemical Medicine in Moscow, said in a press release. "A more complete understanding of potential targets for natural and synthetic agents could help scientists to develop efficient antichlamydial drugs."

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