Mucosal-associated invariant T (MAIT) cells represent an innate T-cell population that can recognize ligands generated by the microbial riboflavin synthesis pathway, presented via the major histocompatibility complex class I-related molecule (MR1). Streptococcus pneumoniae is a major human pathogen that is also associated with commensal carriage; thus, host control at the mucosal interface is c...

Pneumococci killed by acetic acid at pH 4.2, then allowed to become Gram-negative at pH 7.0, under conditions such that no cellular disintegration takes place, release in solution small amounts of a substance which is precipitable by acetic acid, and soluble at neutral reaction. This soluble fraction injected into rabbits by the intravenous route causes the production of antibodies which afford...

Streptococcus pneumoniae (the pneumococcus) is an opportunistic pathogen that colonizes the human nasopharynx asymptomatically. Invasive pneumococcal disease develops following bacterial aspiration into the lungs. Pneumococci within the nasopharynx exist as biofilms, a growth phenotype characterized by surface attachment, encasement within an extracellular matrix, and antimicrobial resistance. ...

The blood of 63 human subjects selected because of the absence of recent infections, was studied for its content of specific antibodies against virulent strains of Types I, II, and III pneumococci before and after intracutaneous injections of minute amounts of pneumococcus products. The simultaneous injection of the specific polysaccharides of all three types of pneumococci and of proteins and ...

Streptococcus pneumoniae is the major pathogen of community-acquired pneumonia. The respiratory epithelium constitutes the first line of defense against invading lung pathogens, including pneumococci. We analyzed the involvement of Toll-like receptors (TLR) and Rho-GTPase signaling in the activation of human lung epithelial cells by pneumococci. S. pneumoniae induced release of interleukin-8 (I...

By interacting with components of the human host, including extracellular matrix (ECM) proteins, Streptococcus pneumoniae has evolved various strategies for colonization. Here, we characterized the interaction of pneumococci with the adhesive glycoprotein vitronectin and the contribution of this protein to pneumococcal uptake by host cells in an integrin-dependent manner. Specific interaction o...

When used in low concentration, formaldehyde increases the rate of autolytic disintegration of pneumococci whereas in large concentrations it completely inhibits autolysis and preserves both the morphological and staining characteristics of the cells. Pneumococci treated with large concentrations of formaldehyde, then washed free of the antiseptic and resuspended in physiological solutions, rap...

MICs of 21 beta-lactams were determined by agar dilution against 283 penicillin-susceptible (pen-S), 122 intermediate (pen-I) and 23 fully penicillin-resistant (pen-R) pneumococci. MICs of all beta-lactams increased with increasing MICs of penicillin. Clometocillin was the most active penicillin against pen-I or pen-R pneumococci. All oral cephalosporins except cefuroxime and cefpodoxime were l...