Interferon-gamma and interleukin-5 production by mice in response to genital infection by the mouse pneumonitis agent of Chlamydia trachomatis.

Abstract

Mice sensitized with a chlamydial detergent extract and then genitally infected by Chlamydia trachomatis have increased genital inflammation characterized by elevated eosinophils, but do not have increased protective immunity. In contrast, mice infected previously by C. trachomatis show strong protective immunity. The authors studied interferon-gamma levels (associated with protective immunity) and interleukin-5 levels (the major cytokine responsible for eosinophilia). To evaluate protective and nonprotective immune responses to chlamydial infection. The authors examined interferon-gamma and interleukin-5 levels in the genitalia during chlamydial genital infection among three groups of mice: extract-sensitized, sham-sensitized, and infected previously. Interferon-gamma levels peaked between 24 and 72 hours after chlamydial infection and then declined among all groups of mice. Overall, interleukin-5 levels increased throughout infection. Interleukin-5 levels apparently continued to increase over the 5-week period after primary infection. Increased interferon-gamma levels were associated with an early response to chlamydial genital infection. Increased interleukin-5 levels were associated with a more persistent immune response.