RESUMO
P64k protein from Neisseria meningitidis is well recognised in sera from individuals convalescent from meningococcal disease or vaccinated with the Cuban antimeningococcal vaccine VA-MENGOC-BC. The presence of the protein in more than 80 meningococcal strains has also been verified. It is immunogenic in animal models and the antibodies elicited show bactericidal activity against meningococci. To further investigate at the molecular level whether lpdA, the gene coding for P64k protein, is conserved among different N. meningitidis strains, a total of 20 strains isolated from different geographic areas were differentiated on the basis of restriction fragment length polymorphism (RFLP) patterns after polymerase chain reaction (PCR) amplification of the lpdA gene and restriction endonuclease digestion with HpaII. Although a total of five different PCR-RFLP patterns were present, nucleotide sequence determination showed that identity levels were as high as 93-99% among the N. meningitidis strains analysed.
Assuntos
Antígenos de Bactérias/genética , Proteínas da Membrana Bacteriana Externa/genética , Genes Bacterianos , Neisseria meningitidis/genética , Sequência de Aminoácidos , Vacinas Bacterianas/genética , Vacinas Bacterianas/imunologia , Sequência Conservada , Vacinas Meningocócicas , Dados de Sequência Molecular , Neisseria meningitidis/classificação , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Especificidade da EspécieRESUMO
By making use of recombinant DNA technology it is possible to characterize meningococcal outer membrane proteins (OMPs) capable of stimulating a host immune response. The lpdA gene, which codes for an OMP (P64k) from Neisseria meningitidis, was cloned in Escherichia coli. The recombinant protein was recognized by sera from patients convalescing from meningococcal disease. The monoclonal antibodies obtained against the recombinant protein recognized the natural protein on a Western blot, and monoclonal antibody 114 was assayed in ELISA with a panel of 85 N. meningitidis strains. The protein was recognized in 81 strains (95.3%); the strains that were not recognized were neither epidemic nor isolated from systemic disease. The complete amino acid sequence of P64k was obtained by automatic sequencing and MS.
