Novel Peptide of <em>Streptococcus pneumoniae</em> Surface Adhesion A (PsaA) Protein Associated with Adherence and Uses Thereof – for Vaccine Candidate, Therapeutic and Diagnostic Development

Streptococcus pneumoniae (S. pneumonia), bacteria commonly referred to as pneumococcus, are a significant cause of disease resulting in 1.5 million deaths every year worldwide according to the World Health Organization. The major types of pneumococcal disease are pneumonia (lung infection), bacteremia (bloodstream infection), and meningitis (infection of the tissue covering of the brain and spinal cord). Less severe pneumococcal illnesses include ear and sinus infections.

CDC scientists have developed a specific amino acid sequence, the P4 peptide, of the Pneumococcal surface adhesin A (PsaA) protein which is an immunogenic epitope and a binding site for adhesion of Streptococcus pneumoniae to human cells. This novel peptide and related sequences, monoclonal antibodies, and uses thereof can be used for vaccine development. Successful polysaccharide vaccines are available in the US, however, countries with limited resources cannot afford these vaccines. PsaA is a streptococcal common protein and a vaccine candidate which could be affordable for all countries. Additionally, there are 90 known serotypes of Streptococcus pneumonia and a need for a vaccine that protects against all known serotypes. The current commercially available vaccines (23-valent polysaccharide (adults); and 7-valent polysaccharide (children)) only protect against more prevalent serotypes. CDC’s peptide technology can also be used for drug receptor modelling, as a highly specific and sensitive diagnostic target, and as an immunogenic mimic of the PsaA protein. Initial rabbit and mouse model research has shown vaccine protection and a therapeutic benefit.