Chlamydia pneumoniae Infection in Polarized Epithelial Cell Lines

Abstract

We set up a polarized cell culture model to study the pathogenicity of a common respiratory tract pathogen, Chlamydia pneumoniae. Immunofluorescence staining of ZO-1 (a tight junction protein) and Na ؉ K ؉ ATPase (a protein pump localized at the basolateral membrane in the polarized epithelial cells), as well as TER measurements, suggested that the filter-grown Calu-3 cells, but not the A549 cells, were polarized when grown on collagen-coated membranes. Both the flat and the filter-grown cultures were infected with C. pneumoniae. Infection in the polarized Calu-3 cultures produced more C. pneumoniae genome equivalents than infection in the flat cultures. However, this progeny was not as infective as that in the flat cultures. The maximum amount of C. pneumoniae was detected at 6 days postinfection in the filter-grown A549 cells, indicating a slower developmental cycle than that observed in the flat A549 cultures. The effect of cycloheximide on the growth of C. pneumoniae in the polarized cells was negligible. Furthermore, the infection in the polarized Calu-3 cells was resistant to doxycycline, and several cytokines were released mainly on the apical side of the polarized cells in response to C. pneumoniae infection. These findings indicate that the growth of chlamydiae was altered in the filter-grown epithelial culture system. The diminished production of infective progeny of C. pneumoniae, together with the resistance to doxycycline and polarized secretion of cytokines from the infected Calu-3 cells, suggests that this model is useful for examining epithelial cell responses to C. pneumoniae infection, and it might better resemble in vivo infection in respiratory epithelial cells.

TRAIL (CD253) Sensitizes Human Airway Epithelial Cells to Toxin-Induced Cell Death

“…Calu-3 cells are a lung adenocarcinoma line widely accepted as a model to study drug and nanomaterial interactions with pulmonary epithelium ( 27 – 31 ). Calu-3 cells have also been used as a model to assess transcytosis of botulinum toxin ( 32 ) and mucosal IgA ( 33 ), as well as infection by respiratory pathogens ( 34 ).…”

Chlamydial Antibiotic Resistance and Treatment Failure in Veterinary and Human Medicine

“…Polarized Calu-3 cultures produced fewer infectious EB than did “flat” cultures, suggesting that C. pneumoniae development differs when host cells are grown in the more biologically relevant polarized condition. Notably, the DOX MBC (minimal antibiotic concentration that eliminated EB production) was >33-fold higher in polarized compared to flat Calu-3 cells, indicating that C. pneumoniae is less antibiotic sensitive when growing in polarized cells [ 47 ]. Oxygen concentration also alters chlamydial antibiotic sensitivity in culture.…”

Heat shock protein 10 of Chlamydophila pneumoniae induces proinflammatory cytokines through Toll-like receptor (TLR) 2 and TLR4 in human monocytes THP-1

“…Therefore, we conducted the removal of LPS from CHSP10 by Endotoxin Removing Gel or preincubation with polymyxin B. LPS is heat-resistant and is not easily destroyed by thermal treatment (Gao et al 2006), while the protein can be broken by heat, which leads to changes of its function. A549, which was often used in vitro studies of C. pneumoniae infection (Törmäkangas et al 2010), failed to produce TNF-alpha in our research. It is not consistent with what has been shown earlier for induction of TNFalpha, IL-8, and IFN-gamma in A549 cells during C. pneumoniae infection (Yang et al 2003).…”