The HMW1/HMW2-like adhesion proteins of nontypeable Haemophilus influenzae (NTHI) are expressed by 75% of NTHI strains. Antibodies directed against these proteins are opsonophagocytic in vitro and are protective in an animal model of infection. The objective of the present study was to determine the opsonophagocytic activity of high-titer anti-HMW1/HMW2 immune sera against both homologous and h...

The HMW1 and HMW2 adhesins of nontypeable Haemophilus influenzae are high-molecular weight proteins that are secreted by the two-partner secretion (TPS) pathway, also known as the Type Vb secretion pathway [1,2]. TPS systems typically consist of a large extracellular protein called a TpsA protein (encoded by a tpsA gene) and a cognate outer membrane pore-forming translocator protein called a Tp...

The cytoskeletal proteins HMW1 and HMW2 are components of the terminal organelle of the cell wall-less bacterium Mycoplasma pneumoniae. HMW1 is required for a tapered, filamentous morphology but exhibits accelerated turnover in the absence of HMW2. Here, we report that a reciprocal dependency exists between HMW1 and HMW2, with HMW2 subject to accelerated turnover with the loss of HMW1. Furtherm...

In patients with chronic obstructive pulmonary disease (COPD), the lower respiratory tract is commonly colonized by bacterial pathogens, including nontypeable Haemophilus influenzae. The H. influenzae HMW1 and HMW2 adhesins are homologous proteins that promote bacterial adherence to respiratory epithelium and are the predominant targets of the host immune response. These adhesins undergo graded...

The genomic sequence of Mycoplasma pneumoniae establish this cell-wall-less prokaryote as among the smallest known microorganisms capable of self-replication. However, this genomic simplicity and corresponding biosynthetic austerity are sharply contrasted by the complex terminal structure found in this species. This tip structure (attachment organelle) directs colonization of the human respirat...

The Haemophilus influenzae HMW1 adhesin is a high-molecular weight protein that is secreted by the bacterial two-partner secretion pathway and mediates adherence to respiratory epithelium, an essential early step in the pathogenesis of H. influenzae disease. In recent work, we discovered that HMW1 is a glycoprotein and undergoes N-linked glycosylation at multiple asparagine residues with simple...

The HMW1 and HMW2 proteins are highly immunogenic adhesins expressed by approximately 75% of nontypeable Haemophilus influenzae (NTHi) strains, and HMW1- and HMW2-specific antibodies can mediate opsonophagocytic killing of NTHi. In this study, we assessed the ability of HMW1- and HMW2-specific antibodies in sera from healthy adults and convalescent-phase sera from children with NTHi otitis medi...

A cell-free system was used to characterize the phosphorylation of Mycoplasma pneumoniae proteins HMW1 and HMW2, which are involved in the adherence of this organism to human tracheal epithelium during infection. The pH and cation requirements for phosphorylation of HMW1 and HMW2 were determined, and the effects of glycolytic intermediates, cyclic AMP, and eukaryotic kinase-phosphatase inhibito...

Nontypeable Haemophilus influenzae (NTHi) is a common cause of localized respiratory tract disease and initiates infection by colonizing the nasopharynx. Approximately 75 to 80% of NTHi clinical isolates produce proteins that belong to the HMW family of adhesins, which are believed to facilitate colonization. The prototype HMW adhesins are designated HMW1 and HMW2 and were identified in NTHi st...

Cytadherence proteins of Mycoplasma pneumoniae are localized at the attachment organelle, which is involved in adhesion, gliding motility, and cell division. The localization of these proteins in cytadherence-deficient mutants was examined by immunofluorescence microscopy. In the class I-2 mutant, which has a frameshift mutation in the hmw2 gene, fluorescent foci for HMW1 and HMW3 were found wi...