Antibody and Cytokine Responses in a Mouse Pulmonary Model of Shigella flexneriSerotype 2a Infection

摘要

A murine pulmonary model was used to study the mucosal immune response toShigella flexneri 2a infection. Inoculation of Balb/cJ mice with shigellae via the intranasal route resulted in bacterial invasion of the bronchial and alveolar epithelia with acute suppurative bronchiolitis and lethal pneumonia. Significant protection against a lethal dose of S. flexneri 2a was achieved in mice previously infected with two sublethal doses of the homologous strain. Over the course of two sublethal infections, mice developed IgG and IgA antibodies recognizing lipopolysaccharide and invasion plasmid antigens. Immune mice developed significantly elevated levels of pulmonary interferon-gamma within 6 h of challenge, while naive control mice developed elevated levels of this cytokine later during the initial 24-h period. Both groups also had elevated levels of tumor necrosis factor-alpha within 6 h of challenge, but control mice had