Infection of untreated primary human amnion monolayers with Chlamydia trachomatis

For development of a laboratory model for chlamydial infection of the human genital tract, untreated primary human epithelial cell monolayers, prepared from each of four placentas, were infected with a stock strain of Chlamydia trachomatis isolated from the nasopharynx of an infant with pneumonia. Infectivity titrations were performed with use of standard procedures of chlamydial inoculation, and inclusions grown in amnion cell monolayers and in McCoy cells were measured versus infectious units inoculated. By linear regression analysis, untreated human amnion cells (y = 0.948x + 4.63, r = 0.9255) were as susceptible as McCoy cells treated with diethylaminoethyl dextran and 5-iodo-2-deoxyuridine (y = 1.104x + 5.35, r = 0.9804). Human amnion may prove a valuable model for study of human chlamydial infection and may have important implications for investigation of clinical disease.