title: The advantage of mucosal immunization for polysaccharide-specific memory responses in early life.
abstract: The aim of vaccination is to rapidly elicit protective immunity and generate memory for sustained protection. We studied the induction and persistence of polysaccharide (PS)-specific memory in neonatal and infant mice primed with pneumococcal conjugate (Pnc1-TT) by assessing the response to native pneumococcal PS (PPS-1), the kinetics of the PPS-1-specific IgG response to a second Pnc1-TT dose and affinity maturation. A subcutaneous (s.c.) Pnc1-TT booster induced a rapid increase in PPS-1-specific IgG, indicating efficient priming for memory by a single dose of Pnc1-TT already at 1 week of age. High levels were maintained for >12 weeks. However, a PPS-1 booster induced no response in neonatal or infant mice. The adjuvant LT-K63 significantly enhanced the IgG response and affinity to Pnc1-TT by both the s.c. and the intranasal (i.n.) route in all age groups. In neonatal and infant mice, PPS-1 and LT-K63 induced a booster response only when given i.n. following either s.c. or i.n. priming with Pnc1-TT and LT-K63. In contrast, PPS-1 with or without LT-K63 administered s.c. compromised the ongoing PPS-1-specific response elicited in neonatal mice by either s.c. or i.n. priming with Pnc1-TT and LT-K63. These results demonstrate the advantage of the mucosal route for elicitation of PS-specific memory responses in early life.
authors.affiliation: Department of Immunology, Landspitali-University Hospital, Reykjavik, Iceland.
authors.forename: Stefania P
authors.initials: SP
authors.lastname: Bjarnarson
authors.forename: Håvard
authors.initials: H
authors.lastname: Jakobsen
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Del Giudice
authors.forename: Emanuelle
authors.initials: E
authors.lastname: Trannoy
authors.forename: Claire-Anne
authors.initials: CA
authors.lastname: Siegrist
authors.forename: Ingileif
authors.initials: I
authors.lastname: Jonsdottir
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000276:immunology; D004768:Enterotoxins / Q000276:immunology; D029968:Escherichia coli Proteins / Q000276:immunology; D018928:Immunity, Mucosal / Q000276:immunology*; D007156:Immunologic Memory / Q000276:immunology*; D051379:Mice; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D014612:Vaccines / Q000276:immunology*
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D011135:Polysaccharides, Bacterial; D014612:Vaccines; C450843:pneumococcal polysaccharide type 1; C027538:heat-labile enterotoxin, E coli