Current design strategies for
vaccines against certain microbial pathogens, including Chlamydia trachomatis, require the induction and targeting of specific immune effectors to the local sites of
infection known as the mucosal effector sites.
Chemokines and their receptors are important mediators of leukocyte trafficking and of the controlled recruitment of specific leukocyte clonotypes during host defense against
infections and during
inflammation. We analyzed the dynamics of
chemokine and
chemokine receptor expression in genital mucosae during genital chlamydial
infection in a murine model to determine how these molecular entities influence the development of immunity and the clearance of
infection. A time course study revealed an increase of up to threefold in the levels of expression of
RANTES,
monocyte chemotactic protein 1 (MCP-1),
gamma-interferon-inducible
protein 10 (IP-10),
macrophage inflammatory protein 1alpha (MIP-1alpha), and
intercellular adhesion molecule type 1 (ICAM-1) after genital
infection with the C. trachomatis agent of mouse
pneumonitis. Peak levels of expression of
RANTES, MCP-1, and
MIP-1alpha occurred by day 7 after primary
infection, while those of IP-10 and
ICAM-1 peaked by day 21. Expression levels of these molecules decreased by day 42 after primary
infection, by which time all animals had resolved the
infection, suggesting an
infection-driven regulation of expression. A rapid upregulation of expression of these molecules was observed after
secondary infection. The presence of cells bearing the
chemokine receptors CCR5 and CXCR3, known to be preferentially expressed on Th1 and dendritic cells, was also synchronous with the kinetics of immune induction in the genital tract and clearance of
infection. Results demonstrated that genital chlamydial
infection is associated with a significant induction of
chemokines and
chemokine receptors that are involved in the recruitment of Th1 cells into the site of
infection. Future studies will focus on how selective modulation of
chemokines and their receptors can be used to optimize long-term immunity against CHLAMYDIA: