When a woman becomes infected with Chlamydia, the first white blood cells that arrive at the scene to fight the infection are not the most effective. This is shown by a thesis from the Sahlgrenska Academy. This discovery could pave the way for the relatively rapid development of a vaccine against Chlamydia.
"Now that we know how the body defends itself against the Chlamydia bacteria, we can develop a vaccine that optimises that defence. We have a basic understanding of how the vaccine could work, but some work remains to be done. We believe that it will take a few years before the vaccine becomes a reality," says researcher Ellen Marks, the author of the thesis.
The body defends itself against infections with a type of white cell called the T lymphocyte. When these blood cells take on the bacteria, they trigger an inflammation that can damage tissue, so there are also other similar blood cells whose main task is to reduce the inflammation and protect tissue. Ellen Marks and her colleagues are the first research team to discover that these anti-inflammatory forces predominate in the lower parts of the female genital tract, mainly mediated by a hormone called IL-10, which is highly protective against tissue damage.
"The result is that the T lymphocytes that could fight Chlamydia are not concentrated in the lower vagina, and the infection can move up towards the womb and fallopian tubes relatively unhindered," says Ellen Marks.
The research team already has a concept of how a vaccine based on this new understanding could work, and they have also tested it on mice.
"The method of administration is an important remaining issue. Previous research has shown that injections don't work, and so the vaccine will probably need to be given either as a nasal spray or in the form of a cream applied into the vagina," says Ellen Marks.
This research is being done at MIVAC (the Mucosal Immunology and Vaccine Center) - the Sahlgrenska Academy's strategic research centre. Researchers at the centre are developing novel methods of treating diseases that affect our mucous membranes.
FACTS ABOUT CHLAMYDIA
The incidence of Chlamydia infection in Sweden has increased since the mid-nineties, especially in people under the age of 24. Last year, over 40 000 new cases were reported to the Swedish Institute for Infectious Disease Control. The disease is caused by the bacterium Chlamydia trachomatis, which is transmitted by unprotected sexual contact. Many don't realise that they have been infected, because Chlamydia infection often has no symptoms at all. Without effective antibiotic treatment the infection can become chronic and may even lead to infertility.
Supervisor: Professor Nils Lycke, tel. +46 (0)31-786 63 21,
Thesis for the degree of Doctor of Medical Science at the Department of Microbiology and Immunology, Institute of Biomedicine, the Sahlgrenska Academy.
Title of thesis: Genital tract CD4+ T cells for vaccination and protection against Chlamydia trachomatis
The thesis has been defended.
You can read the complete thesis here: http://hdl.handle.net/2077/21075
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