Increased virulence of Neisseria meningitidis after in vitro iron-limited growth at low pH

作者：D Brener, I W DeVoe, Bruce E. Holbein · 发表于：Infection and Immunity · 年份：1981 · DOI：10.1128/iai.33.1.59-66.1981 · 被引用次数：65 · 研究领域：Bacterial Infections and Vaccines、Antibiotic Resistance in Bacteria、Streptococcal Infections and Treatments

At low pH (6.6) and under conditions of iron limitation, Neisseria meningitidis group B (strain SD1C) exhibited an atypical outer membrane protein profile and an increased relative virulence for the mouse. Cells grown in a buffered medium were effectively deprived of iron by the addition of ethylenediamine-diorthohydroxyphenylacetate. The pH of the medium selected for characteristic colonial morphologies: type M3 predominated at pH 6.6, and type M5 predominated at pH 7.7. A mixed population of M1, M3, and M5 colonies was observed at pH 7.2. Isolated outer membrane proteins were analyzed by sodium dodecyl 99 99 sulfate-polyacrylamide gel electrophoresis, and surface exposed proteins were labeled by the [125I]lactoperoxidase method and subsequently identified by autoradiography. Cells grown at pH 6.6 elaborated a major outer membrane protein (protein III; molecular weight, 69,000), which was also present in the outer membrane of iron-limited cells grown at pH 7.2. At pH 7.2 in an iron-sufficient medium, protein III was present only in small quantities in sodium dodecyl sulfate-polyacrylamide gel was present only in small quantities in sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels. A study of the relative virulence (50% lethal dose) of the meningococcus for C57/BL mice revealed that iron-limited cells grown at low pH had an increased relative virulence 1,200-fold (50% lethal dose, 4.0 CFU) greater than that of cells grown in the same medium but at pH 7.2 and wit...