Neisseria lactamica, a commensal bacterium that is non-pathogenic to human beings and that is usually found in the upper respiratory tract of children, is closely related to the pathogenic species Neisseria meningitidis. A protocol was proposed to study the immunogenicity of killed whole cells of N. lactamica, N. meningitidis, N. sicca or N. meningitidis c (carrier-isolated) by i.n. immunization in rabbits,considering the natural pathogen entry route. Adult rabbits were inoculated i.n with oropharynx-isolated N. lactamica, N. meningitidis, N. sicca or N. meningitidis carrier strain (c), at a concentration of 1.0 optical density unit at 650nm in a volume of 500 L. The rabbits were immunized four times at sevendays intervals. The rabbits developed levels of specific IgG antibodies in serum, as determined by ELISA using whole cells of homologous and heterologous strains. Serum from rabbits immunized with N. lactamica, N. meningitidis, and N. sicca or N. meningitidis c strain, showed IgG antibodies reactive to 5 to 190kDa antigens on immunoblotting with high avidity.

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A rapid and efficient method for preparing monoclonal antibody (MAb) serotypes using Neisseria meningitidis outer membrane were used in BALB/c mouse footpads for the immunization. The popliteal lymph nodes were isolated 19 days later for MAb-producing hybridomas, from which the MAbs against the 37 kDa protein were screened. Variations in class 2/3 (PorB) proteins form the basis for meningococcal serotyping. This is the first report on the preparation of MAbs against N. meningitidis that is specific to PorB protein using popliteal lymph nodes. The new monoclonal antibodies were specific for PorB outer membrane protein FL24(PL)Br, a new serotype 24 class 3 antigens of non-typeable (NT:NST) serogroup B strain, and FL14(PL)Br specific for the serotype 14, and reacted with the S3446 reference strain analyzed. A total of 12% of the case isolates reacted with one or more of the monoclonal antibodies. The high-affinity MAbs produced by hybridoma methodology provide a basis for further research on the pathogenesis and early diagnosis of meningococcus.

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anticorpos produzidos pelos coelhos imunizados intranasalmente com N. meningitidis. Anticorpos IgG de alta avidez foram produzidos, embora não tenha sido determinada uma significativa correlação entre atividade bactericida e a indução de anticorpos IgG de alta avidez, principalmente nos coelhos imunizados com N. lactamica. A imunização RESUMO intranasal usando whole cells de N. lactamica foi adequada para sensibilizar eficientemente o sistema imune de mucosa no modelo coelho.