The alarming increase in antimicrobial resistance in the last decades has prompted the search for alternatives to control infectious diseases. Antimicrobial peptides (AMPs) represent a heterogeneous class of molecules with ample antibacterial, antiviral, and antifungal effects. They can be found in many organisms, including all classes of vertebrates, providing a valuable source of new antimicrobial agents.
View Article and Find Full Text PDFThe common pathogen Group A (GAS, ) is an extracellular bacterium that is associated with a multitude of infectious syndromes spanning a wide range of severity. The surface-exposed M protein is a major GAS virulence factor that is also target for protective antibody responses. In this study, we use a murine immunization model to investigate aspects of the cellular and molecular foundation for protective adaptive immune responses generated against GAS.
View Article and Find Full Text PDFPLoS One
December 2022
PspA and pneumolysin are two important vaccine candidates, able to elicit protection in different models of pneumococcal infection. The high immunogenic potential of PspA, combined with a possible adjuvant effect of pneumolysin derivatives (due to their ability to interact with TLR-4) could greatly improve the immunogenicity and coverage of a protein-based pneumococcal vaccine. A chimeric protein including the N-terminal region of PspA in fusion with the pneumolysin derivative, PlD1, has been shown to induce high antibody levels against each protein, and protect mice against invasive challenge.
View Article and Find Full Text PDFStreptococcus pneumoniae is a human pathogen that colonizes the naso and/or oropharynx and can cause otitis, pneumonia, bacteremia and meningitis. To broaden the protection against pneumococcus, several pneumococcal proteins have been investigated as vaccine candidates. In this study we analyzed the immunological response induced by mouse subcutaneous immunization with a fusion of the Polyamine transport protein D (PotD) and a pneumolysin derivative (PdT), resulting in a hybrid rPotD-PdT protein.
View Article and Find Full Text PDFFront Cell Infect Microbiol
June 2022
The ability to form biofilms is a crucial virulence trait for several microorganisms, including - a Gram-negative encapsulated bacterium often associated with nosocomial infections. It is estimated that 65-80% of bacterial infections are biofilm related. Biofilms are complex bacterial communities composed of one or more species encased in an extracellular matrix made of proteins, carbohydrates and genetic material derived from the bacteria themselves as well as from the host.
View Article and Find Full Text PDFKlebsiella pneumoniae is a bacterium capable of colonizing mucous membranes, causing serious infections. Widespread antibiotic resistance in K. pneumoniae-either through intrinsic mechanisms or via acquisition from different species, especially in hospital environments-limits the therapeutic options against this pathogen, further aggravating the disease burden.
View Article and Find Full Text PDFWith the alarming increase of infections caused by pathogenic multidrug-resistant bacteria over the last decades, antimicrobial peptides (AMPs) have been investigated as a potential treatment for those infections, directly through their lytic effect or indirectly, due to their ability to modulate the immune system. There are still concerns regarding the use of such molecules in the treatment of infections, such as cell toxicity and host factors that lead to peptide inhibition. To overcome these limitations, different approaches like peptide modification to reduce toxicity and peptide combinations to improve therapeutic efficacy are being tested.
View Article and Find Full Text PDFPneumococcal diseases remain a substantial cause of mortality in young children in developing countries. The development of potentially serotype-transcending vaccines has been extensively studied; ideally, such a vaccine should include antigens that are able to induce protection against colonization (likely mediated by interleukin-17A [IL-17A]) and invasive disease (likely mediated by antibody). The use of strong adjuvants or alternative delivery systems that are able to improve the immunological response of recombinant proteins has been proposed but poses potential safety and practical concerns in children.
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