Open AccessThe developmental cycle of Ehrlichia chaffeensis in vertebrate cells
Author(s) -
Zhang Jianzhi,
Popov Vsevolod L.,
Gao Si,
Walker David H.,
Yu Xuejie
Publication year - 2007
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1111/j.1462-5822.2006.00812.x
Subject(s) - ehrlichia chaffeensis , biology , microbiology and biotechnology , confocal microscopy , intracellular , virology , ehrlichia , tick
Summary Ehrlichia chaffeensis , an obligatory intracellular bacterium, has two forms in mammalian cells: small dense‐cored cells (DC) with dense nucleoid and larger reticulate cells (RC) with uniformly dispersed nucleoid. We have determined by electron microscopy that DC but not RC attaches to and enters into the host cells and RC but not DC multiples inside the host cells. Analysis of outer membrane protein expression by confocal microscopy showed that RC expressed the 28 kDa outer membrane protein (p28), the intermediate form, which were transforming from RC to DC, expressed both gp120 and p28, and the mature DC expressed gp120 only. The TCID 50 of DC is 6 log 10 higher than RC. We conclude that E. chaffeensis has a developmental cycle, in which the DC attaches to and enters into the host cells, and transforms into RC and the RC multiplies by binary fission for 48 h and then matures into DC at 72 h.