The LafB antigen as a universal vaccine candidate against pneumococcal infections.

Laurye VAN MAELE, Institut Pasteur de Lille -Team Bacteria, Antibiotics and Immunity. Center for Infection and Immunity of Lille

Several vaccines targeting bacterial pathogens show reduced efficacy in the context of viral infection indicating a new vaccinology approach is required to protect against such superinfections. To find antigens for the human pathogen Streptococcus pneumoniae that are effective following influenza infection, we performed CRISPRi-seq in a murine model of superinfection and identified the highly conserved lafB gene as virulence factor. We show that LafB is a membrane-associated, intracellular protein that catalyzes the formation of galactosyl-glucosyl-diacylglycerol, a glycolipid we show is important for cell wall homeostasis. Respiratory vaccination with recombinant LafB, in contrast to subcutaneous vaccination, was highly protective against all serotypes tested in a murine model. In contrast to standard pneumococcal capsule-based vaccines, protection did not require LafB-specific antibodies but was dependent on airway CD4+ T helper 17 cells. Healthy human individuals can elicit LafB-specific immune responses, suggesting its merit as a universal pneumococcal vaccine antigen that remains effective following influenza infection.

Thursday, January 25th, 2024 from 11:30 AM to 12:30 PM

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