Neisseria sp.

Details

Neisseria sp.

 

Gramnegatives Bakterium

 

Befund

Befund, durch Abstrich im Chinchilla Rachenraum, mit Haemophilus sp. und Escherichia coli

 

Symptome aller 3 Bakterien zusammen

  • extremes Zähne knirschen
  • unregelmäßiges sabbern
  • leichter Gewichtsverlust

 

 

1995, 361, Session J, Podium

Homologous and heterologous Streptococcus pneumoniae (Sp) serotype protection induced by pneumococcal polysaccharide-protein conjugate vaccines 

 *G.S. Giebink, J.D. Meier, M.K. Quartey, C.L. Liebeler (Univ.of Minnesota School of Med., Minneapolis, MN)

Many Sp serotypes that cause otitis media (OM) in children are closely related biochemically, but cross-protection among serotypes within serogroups has not been studied. We studied the immunogenicity and middle ear (ME) protection within serogroups using vaccines composed of Sp capsular polysaccharides (PS) conjugated to outer membrane protein complex from Neisseria meningitidis. Chinchillas were given two doses of a tetravalent vaccine composed of four PS-protein conjugates (types 6B, 14, l9F, 23F) or placebo vaccine. Vaccine efficacy was tested by injecting both ME on day 56 after vaccination with one of the vaccine serotypes (6B, l9F) or with closely related serotypes in the same serogroups (6A, l9A). Serum anti-PS IgG antibodies (aby) were measured using a sensitive ELISA. ME scores derived from tympanic membrane appearance, tympanometry, and MEF culture on days 3, 7, 10 and 14 after challenge reflected OM severity. Vaccination induced at least a 2-fold aby rise against 6A, 6B, l9A and l9F PS in 76%, 100%, 94% and 94% of animals, respectively. Geometric mean day 56 aby titers were higher for PS types contained in the vaccine than for related PS types (6B vs 6A: 2.16 vs 0.81 µg/mL, p=0.06; l9F vs l9A: 2.72 vs 1.32, p=0.28). No aby was produced in animals given placebo vaccine. 6B vaccine prevented Sp OM in 62% of chinchillas challenged with 6B Sp and 37% challenged with 6A Sp (p=0.20). l9F vaccine prevented Sp OM in 100% of chinchillas challenged with l9F Sp and 12% challenged with l9A Sp (p<0.01). All animals given placebo vaccine developed Sp OM after challenge. Post-challenge otitis media severity for individual animals was significantly correlated with pre-challenge (day 56) serum aby for type 6A (r=-0.67, p=0.003), 6B (r=-0.50, p=0.046), and l9F (r=-0.56, p=0.011), but not l9A (r=-0.32, p=0.22). Thus, types 6B and l9F PS-protein conjugates were immunogenic in chinchillas, elicited serotype-specific and heterologous aby within serogroups, and afforded significant protection for the homologous and variable protection for heterologous serotypes. Otitis media severity was inversely correlated with serum anti-PS aby at the time of challenge.

Supported by a grant from Merck Research Laboratories