Immunization with a whole cell vaccine reduces pneumococcal nasopharyngeal density and shedding, and middle ear infection in mice

Vaccine. 2024 Feb 12:S0264-410X(24)00131-2. doi: 10.1016/j.vaccine.2024.01.104. Online ahead of print.ABSTRACTPneumococcal Conjugate Vaccines (PCVs) have substantially reduced the burden of disease caused by Streptococcus pneumoniae (the pneumococcus). However, protection is limited to vaccine serotypes, and when administered to children who are colonized with pneumococci at the time of vaccination, immune responses to the vaccine are blunted. Here, we investigate the potential of a killed whole cell pneumococcal vaccine (WCV) to reduce existing pneumococcal carriage and mucosal disease when given therapeutically to infant mice colonized with pneumococci. We show that a single dose of WCV reduced pneumococcal carriage density in an antibody-dependent manner. Therapeutic vaccination induced robust immune responses to pneumococcal surface antigens CbpA, PspA (family 1) and PiaA. In a co-infection model of otitis media, a single dose of WCV reduced pneumococcal middle ear infection. Lastly, in a two-dose model, therapeutic administration of WCV reduced nasal shedding of pneumococci. Taken together, our data demonstrate that WCV administered in colonized mice reduced pneumococcal density in the nasopharynx and the middle ear, and decreased shedding. WCVs would be beneficial in low and middle-income settings where pneumococcal carriage in children is high.PMID:38350767 | DOI:10.1016/j.vaccine.2024.01.104

Source: Vaccine - February 13, 2024 Category: Allergy & Immunology Authors: Jayne Manning Sam Manna Eileen M Dunne Viktoria Bongcaron Casey L Pell Natalie L Patterson Sacha D Kuil Poshmaal Dhar David Goldblatt E Kim Mulholland Paul V Licciardi Roy M Robins-Browne Richard Malley Odilia Wijburg Catherine Satzke Source Type: research