Innate immune response in avian macrophages elicited by Chlamydia psittaci

Chlamydia psittaci is a gram-negative, obligate, intracellular bacterium, which mainly infects birds and mammals. Not much is known about innate immunity initiated by C. psittaci. The focus of the present study is on chicken macrophage activation and expression of cytokine, chemokine, caspase-1, iNOS and TLR genes during the early phase and mid-cycle period of the developmental cycle of the highly virulent C. psittaci strain 92/1293. C. psittaci significantly augmented the transcript levels for all genes investigated, especially during the mid-cycle period. These results demonstrate a robust innate immune response of chicken macrophages initiated by a C. psittaci infection

Chlamydial infection from outside to inside

Chlamydia are obligate intracellular bacteria, characterized by a unique biphasic developmental cycle. Specific interactions with the host cell are crucial for the bacteria's survival and amplification because of the reduced chlamydial genome. At the start of infection, pathogen-host interactions are set in place in order for Chlamydia to enter the host cell and reach the nutrient-rich peri-Golgi region. Once intracellular localization is established, interactions with organelles and pathways of the host cell enable the necessary hijacking of host-derived nutrients. Detailed information on the aforementioned processes will increase our understanding on the intracellular pathogenesis of chlamydiae and hence might lead to new strategies to battle chlamydial infection. This review summarizes how chlamydiae generate their intracellular niche in the host cell, acquire host-derived nutrients in order to enable their growth and finally exit the host cell in order to infect new cells. Moreover, the evolution in the development of molecular genetic tools, necessary for studying the chlamydial infection biology in more depth, is discussed in great detail

Avian chlamydiosis

B

MOMP-based DNA vaccination against Chlamydia trachomatis infection in a pig model

C