A chlamydia vaccine has triggered immune responses in an early trial, raising hopes that one day it might help curb the spread of the sexually transmitted infection.
Currently a Chlamydia vaccine is unavailable and Chlamydia is the most common bacterial infection. In the new trial results, published April 11 in the journal Lancet Infectious Diseases, the vaccine was found to be safe and it also prompted an antibody response.
Chlamydia also remains one of the most common causes of infertility in women and can also cause an eye infection that leads to vision loss in 1.9 million people worldwide.
In the new Phase 1 trial, which took place from 2020 through 2022, participants were equally split between healthy men and women with an average age of 26. The researchers tested several different dosages for the vaccine, and participants got either the vaccine or a placebo on three separate days over a period of almost four months.
Despite the promising results, many questions remain.
The researchers are already planning to launch a larger, Phase 2 trial that would weigh the vaccine's effectiveness.
The hope is that one day the vaccine could prevent both infections in the reproductive system and the eyes, said study author Jes Dietrich, a senior scientist at Statens Serum Institut in Denmark.
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ABSTRACT
The clinical development of an effective Chlamydia vaccine requires in-depth understanding of how well protective pre-clinical immune signatures translate to humans. Here, we report a comparative immunological characterization of CTH522/CAF®01 in female mice and humans. We find a range of immune signatures that translate from mouse to human, including a Th1/Th17 cytokine profile and antibody functionality. We identify vaccine-induced T cell epitopes, conserved among Chlamydia serovars, and previously found in infected individuals. Using the mouse model, we show that the common immune signature protected against ascending infection in mice, and vaccine induced antibodies could delay bacterial ascension to the oviduct, as well as development of pathology, in a T cell depleted mouse model. Finally, we demonstrate long-lasting immunity and protection of mice one year after vaccination. Based on the results obtained in the present study, we propose to further investigate CTH522/CAF®01 in a phase IIb study.
Currently a Chlamydia vaccine is unavailable and Chlamydia is the most common bacterial infection. In the new trial results, published April 11 in the journal Lancet Infectious Diseases, the vaccine was found to be safe and it also prompted an antibody response.
Chlamydia also remains one of the most common causes of infertility in women and can also cause an eye infection that leads to vision loss in 1.9 million people worldwide.
In the new Phase 1 trial, which took place from 2020 through 2022, participants were equally split between healthy men and women with an average age of 26. The researchers tested several different dosages for the vaccine, and participants got either the vaccine or a placebo on three separate days over a period of almost four months.
Despite the promising results, many questions remain.
The researchers are already planning to launch a larger, Phase 2 trial that would weigh the vaccine's effectiveness.
The hope is that one day the vaccine could prevent both infections in the reproductive system and the eyes, said study author Jes Dietrich, a senior scientist at Statens Serum Institut in Denmark.
------------------------------------------------------------------------------------------------------------------------------------------------------------------
ABSTRACT
The clinical development of an effective Chlamydia vaccine requires in-depth understanding of how well protective pre-clinical immune signatures translate to humans. Here, we report a comparative immunological characterization of CTH522/CAF®01 in female mice and humans. We find a range of immune signatures that translate from mouse to human, including a Th1/Th17 cytokine profile and antibody functionality. We identify vaccine-induced T cell epitopes, conserved among Chlamydia serovars, and previously found in infected individuals. Using the mouse model, we show that the common immune signature protected against ascending infection in mice, and vaccine induced antibodies could delay bacterial ascension to the oviduct, as well as development of pathology, in a T cell depleted mouse model. Finally, we demonstrate long-lasting immunity and protection of mice one year after vaccination. Based on the results obtained in the present study, we propose to further investigate CTH522/CAF®01 in a phase IIb study.
TFS brother. 
