INTRANASAL IMMUNIZATION OF MICE WITH PSPA (PNEUMOCOCCAL SURFACE PROTEIN-A) CAN PREVENT INTRANASAL CARRIAGE, PULMONARY INFECTION, AND SEPSISWITH STREPTOCOCCUS-PNEUMONIAE

Many pathogens, including Streptococcus pneumoniae, are carried asympt omatically on the nasopharyngeal mucosa and spread among individuals b y close contact, Clinical disease results when pneumococci escape from the mucosa and invade sterile sites, Although systemic immunity can p revent invasive disease, control of person-to-person spread is probabl y dependent on immunity acting at the mucosal surface, Intranasal immu nization of mice with PspA (pneumococcal surface protein A) or a capsu lar 6B polysaccharide-tetanus toroid conjugate induced mucosal and sys temic antibody responses and provided long-lasting protection against carriage of S. pneumoniae. Resistance to carriage was dependent on muc osal rather than systemic immunity and was effective against heterolog ous strains of heterologous PspA types. Intranasal immunization with P spA also protected against systemic infection following intravenous, i ntratracheal, and intraperitoneal challenge.