Pub Quiz time: What obligate intracellular pathogen infects the eye and is a major cause of blindness? (As you may guess I don’t
get to many pub quizzes!). The answer is Chlamydia, with a bonus point for the
full name Chlamydia trachomatis. And yes it is the same type of bacteria that
causes the sexually transmitted infection, chlamydia. In fact there are 12
strains of chlamydia, a-c cause the eye disease, d-k cause the sexually
transmitted infection and L causes an invasive sexually transmitted infection. Interestingly*,
the way chlamydia infection causes disease in either the eye or the genital
tract is the same. The immune response is too aggressive, leading to damage of
the surrounding tissue, which has bad consequences in sensitive organs such as
the eyes or ovaries.
Chlamydia of the eye
Chlamydia infections causes the disease trachoma, which
leads to 4.9 million cases of blindness annually inlower and middle income
countries. For more information visit the international trachoma initiative. It
is described as a disease of poverty because it is most prevalent in locations
with poor access to clean water. It is also categorised as a neglected tropical
disease by WHO, with the aim that this will encourage a greater research
effort. For example if companies work on these diseases they are eligible for
FDA priority review vouchers which allows them to accelerate licensure of other
drugs. The current treatment regime is to use antibiotics -
Azithromycin . This is cheap and effective especially since Pfizer donate free Zithromax®.
However with antibiotic treatment of bacterial infections there is always a
risk that the bacteria become resistant to the drugs, which then become less
effective. So it is prudent to look for alternative.
Eye protection
In our recently published study, we were investigating new vaccines. Because it is a disease of the eye,
we trying to improve the protective immune response in the eye. We developed a
new technique for measuring antibody (the super molecules that are able to
recognise bacteria by their shape). We observed that some of the new vaccines
we tested led to the measurable antibody in the eye, which might protect
against infection. This work has now lead (in collaboration with our Danish
partners from SSI, Copenhagen, into a clinical trial in people, that will test
vaccines for safety, but also measure antibody in the eye. This work was made
possible by support from the EU as part of a multi centre consortium called
Aditec.
* Interestingly is a horrible science writing device – often
gets irate reviewer’s commenting about the reader getting to decide what is
interesting, but the good thing about writing an unreviewed blog is that I can
say what I like.
PS thanks to Alex (Badamchi) for proofing this and filling in the details
PS thanks to Alex (Badamchi) for proofing this and filling in the details
