An attenuated, or weakened, strain of Chlamydia trachomatis bacteria can be used as a vaccine to prevent or reduce the severity of trachoma, the world's leading cause of infectious blindness, suggest findings from a National Institutes of Health study in monkeys.
"This work is an important milestone in the development of a trachoma vaccine," noted Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID) at NIH. "If this approach demonstrates continued success, the implications could be enormous for the tens of millions of people affected by trachoma, a neglected disease of poverty primarily seen in Asia and sub-Saharan Africa."
In their study, published in the Journal of Experimental Medicine online, scientists from NIAID, led by Harlan Caldwell, Ph.D., describe how they tested their vaccine concept in a series of experiments. First they infected six cynomolgus macaques with the strain of C. trachomatis that they had weakened by removing a small piece of DNA. The scientists observed that the monkeys spontaneously cleared the infection within 14 days with no or minimal signs of ocular disease. The animals then were exposed twice more to the weakened strain at four- and eight-week intervals, but the animals still showed no signs of trachoma despite being infected.
According to Dr. Caldwell, this finding is particularly significant because repeated C. trachomatis infections typically lead to more severe eye disease in people. The infected animals did not develop eye disease, and they all mounted robust immune responses.
The same six macaques then were exposed to a highly virulent strain of C. trachomatis as were six other macaques in a control group that had not been vaccinated. Three of the macaques in the vaccine group showed no signs of infection or disease, and the three others showed greatly reduced infection compared with monkeys in the control group. All six macaques in the control group became infected and displayed moderate to severe eye disease that persisted for between two and four months.
Macaques are used in trachoma studies because their immune responses closely predict those of humans. The animals in the study were treated with antibiotics after completion of the experiments, and all recovered completely.
The NIAID researchers are currently exploring how they can move their vaccine into human clinical trials.
If left untreated, prolonged trachoma infection can cause a person's eyelids to fold inward, so that the eyelashes rub the eyeball and scar the cornea. This can result in impaired vision and sometimes blindness. Trachoma is treatable with antibiotics, although in many parts of the world people have limited access to treatment. Currently, there is no vaccine for trachoma. Trachoma experts estimate that approximately 1.3 million people are blind from trachoma, 1.8 million people have low vision as a result of the disease, and an estimated 40 million people have active trachoma. Trachoma is most often spread through direct personal contact, shared towels and other cloths, and flies that have come in contact with the eyes or nose of an infected person.
Chlamydia diseases include sexually transmitted infections, which can result in pelvic inflammatory disease that can cause infertility in women, as well as trachoma. According to the NIAID researchers, findings from this study also could lead to the development of a vaccine against sexually transmitted Chlamydia infections. The Centers for Disease Control and Prevention received more than 1.2 million reports of Chlamydia infections in 2009.
NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.
Reference: L Kari et al. A live-attenuated chlamydial vaccine protects against trachoma in nonhuman primates. The Journal of Experimental Medicine. DOI: 10.1084/jem.20111266
Ken Pekoc | EurekAlert!
Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT
Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
06.12.2016 | Materials Sciences
06.12.2016 | Medical Engineering
06.12.2016 | Power and Electrical Engineering