REACTIVATION OF PERSISTENT CHLAMYDIA-TRACHOMATIS INFECTION IN CELL-CULTURE

Gamma interferon induces persistent chlamydial infections in cell cult ure. These infections are characterized by altered morphologic and bio chemical features of the pathogen. These persistent forms are abnormal ly large and noninfectious and undergo unusual structural and function al changes, including production of a paucity of outer envelope consti tuents and normal levels of the chlamydial hsp60, an immunopathologica l antigen. The current investigation evaluates the events that occur d uring reactivation of infectious Chlamydia trachomatis from persistent ly infected cell cultures. Transfer of persistent chlamydial organisms to gamma interferon-free medium resulted in recovery of infectivity a ccompanied by an increase in levels of structural membrane proteins an d reorganization of aberrant organisms to morphologically typical elem entary bodies. In addition, reactivation of infectious organisms from persistent chlamydiae that were maintained in culture for several week s was demonstrated. These studies show that persistent C. trachomatis maintains viability for extended periods, illustrate the reversibility of immunologically mediated persistent infections, and characterize r eactivation at the ultrastructural and biochemical levels.