Bronchus-associated lymphoid tissue (BALT) and survival in a vaccine mouse model of tularemia.
BACKGROUND
Francisella tularensis causes severe pulmonary disease, and nasal vaccination could be the ideal measure to effectively prevent it. Nevertheless, the efficacy of this type of vaccine is influenced by the lack of an effective mucosal adjuvant.


RESULTS
Mice were immunized via the nasal route with lipopolysaccharide isolated from F. tularensis and neisserial recombinant PorB as an adjuvant candidate. Then, mice were challenged via the same route with the F. tularensis attenuated live vaccine strain (LVS). Mouse survival and analysis of a number of immune parameters were conducted following intranasal challenge. Vaccination induced a systemic antibody response and 70% of mice were protected from challenge as showed by their improved survival and weight regain. Lungs from mice recovering from infection presented prominent lymphoid aggregates in peribronchial and perivascular areas, consistent with the location of bronchus-associated lymphoid tissue (BALT). BALT areas contained proliferating B and T cells, germinal centers, T cell infiltrates, dendritic cells (DCs). We also observed local production of antibody generating cells and homeostatic chemokines in BALT areas.


CONCLUSIONS
These data indicate that PorB might be an optimal adjuvant candidate for improving the protective effect of F. tularensis antigens. The presence of BALT induced after intranasal challenge in vaccinated mice might play a role in regulation of local immunity and long-term protection, but more work is needed to elucidate mechanisms that lead to its formation.
Chiavolini
Damiana
D
Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America.
Rangel-Moreno
Javier
J
Berg
Gretchen
G
Christian
Kate
K
Oliveira-Nascimento
Laura
L
Weir
Susan
S
Alroy
Joseph
J
Randall
Troy D
TD
Wetzler
Lee M
LM
D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology; D001428:Bacterial Vaccines / Q000008:administration & dosage* / Q000276:immunology; D001980:Bronchi / Q000473:pathology*; D004195:Disease Models, Animal; D008221:Lymphoid Tissue / Q000473:pathology*; D051379:Mice; D014406:Tularemia / Q000276:immunology / Q000473:pathology*
D001428:Bacterial Vaccines