Phosphorylcholine Allows for Evasion of Bactericidal Antibody by Haemophilus influenzae

The human pathogen Haemophilus influenzae has the ability to quickly adapt to different host environments through phase variation of multiple structures on its lipooligosaccharide (LPS), including phosphorylcholine (ChoP). During colonization with H. influenzae, there is a selection for ChoP+ phase variants. In a murine model of nasopharyngeal colonization, this selection is lost in the absence of adaptive immunity. Based on previous data highlighting the importance of natural antibody in limiting H. influenzae colonization, the effect of ChoP expression on antibody binding and its bactericidal activity was investigated. Flow cytometric analysis revealed that ChoP+ phase variants had decreased binding of antibody to LPS epitopes compared to ChoP− phase variants. This difference in antibody binding correlated with increased survival of ChoP+ phase variants in the presence of antibody-dependent, complement-mediated killing. ChoP+ phase variants were also more resistant to trypsin digestion, suggesting a general effect on the physical properties of the outer membrane. Moreover, ChoP-mediated protection against antibody binding correlated with increased resilience of outer membrane integrity. Collectively, these data suggest that ChoP expression provides a selective advantage during colonization through ChoP-mediated effects on the accessibility of bactericidal antibody to the cell surface

Site VII, Kiva A from Southeast

Archaeological site records from the Harvard Peabody Archaeological Photographic Collection

Survey Drawing - Beam Pattern, Kiva B, Site VII

Archaeological site records from the Harvard Peabody Archaeological Photographic Collection

Site VII, House VII

Archaeological site records from the Harvard Peabody Archaeological Photographic Collection

Site VII, roof structure at east end

Archaeological site records from the Harvard Peabody Archaeological Photographic Collection

Site I after cleaning of rocks, from South

Archaeological site records from the Harvard Peabody Archaeological Photographic Collection

Site VII, House VII, Southwest corner, ventilator and deflector

Archaeological site records from the Harvard Peabody Archaeological Photographic Collection

Site VII, House I, from Northeast

Archaeological site records from the Harvard Peabody Archaeological Photographic Collection

Survey drawing - Tooele Site 1

Archaeological site records from the Harvard Peabody Archaeological Photographic Collection