Heparan sulfate-like glycosaminoglycan is a cellular receptor for Chlamydia pneumoniae.

Chlamydia pneumoniae is an important human intracellular pathogen; however, the pathogenesis of C. pneumoniae infection is poorly understood, and the bacterial adherence mechanism to host cells is unknown. This study examined the role of glycosaminoglycans (GAGs) in the adhesion of C. pneumoniae to eukaryotic cells. Heparin and heparan sulfate were found to inhibit the attachment of C. pneumoniae to human epithelial cells. Reduction in infectivity resulted from the binding of heparin to the organism. Enzymatic removal of heparan sulfate moieties from the host cell surface led to a marked decrease in C. pneumoniae infectivity. Mutant CHO cell lines that were defective in heparan sulfate biosynthesis were less susceptible to C. pneumoniae infection than was the wild-type cell line. However, preincubation of the GAG-deficient CHO cells with exogenous heparin greatly increased infectivity.