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The use of oligonucleotide probes for meningococcal serotype characterization
C T Sacchi1, A P de Lemos, A M Whitney
1Bacteriology Division, Adolfo Lutz Institute, São Paulo, Brazil. sacchi@usp.br
Abstract:
In the present study we examine the potential use of oligonucleotide probes to characterize Neisseria meningitidis serotypes without the use of monoclonal antibodies (MAbs). Antigenic diversity on PorB protein forms the bases of serotyping method. However, the current panel of MAbs underestimated, by at least 50% the PorB variability, presumably because reagents for several PorB variable regions (VRs) are lacking, or because a number of VR variants are not recognized by serotype-defining MAbs. We analyzed the use of oligonucleotide probes to characterize serotype 10 and serotype 19 of N. meningitidis. The porB gene sequence for the prototype strain of serotype 10 was determined, aligned with 7 other porB sequences from different serotypes, and analysis of individual VRs were performed. The results of DNA probes 21U (VR1-A) and 615U (VR3-B) used against 72 N. meningitidis strains confirm that VR1 type A and VR3 type B encode epitopes for serotype-defined MAbs 19 and 10, respectively. The use of probes for characterizing serotypes possible can type 100% of the PorB VR diversity. It is a simple and rapid method specially useful for analysis of large number of samples.
Insights
Oligonucleotide probes offer a simple, rapid method to characterize Neisseria meningitidis serotypes by analyzing PorB protein variability. This approach overcomes limitations of monoclonal antibodies, potentially typing 100% of PorB variable region diversity.
Area of Science:
- Microbiology
- Molecular Biology
- Immunology
Background:
- Serotyping Neisseria meningitidis is crucial for epidemiology and vaccine development.
- Current serotyping relies on monoclonal antibodies (MAbs) targeting the PorB protein.
- Existing MAb panels underestimate PorB variability, potentially missing key antigenic differences.
Purpose of the Study:
- To evaluate oligonucleotide probes for characterizing Neisseria meningitidis serotypes.
- To assess if probes can identify PorB protein variability missed by MAbs.
- To develop a more comprehensive serotyping method.
Main Methods:
- Determining the porB gene sequence of serotype 10 N. meningitidis.
- Aligning sequences and analyzing individual PorB variable regions (VRs).
- Using specific DNA probes (21U and 615U) against 72 N. meningitidis strains.
Main Results:
- Oligonucleotide probes confirmed epitopes recognized by serotype-defining MAbs.
- Probe 21U (VR1-A) and 615U (VR3-B) correlate with serotypes 19 and 10, respectively.
- This method can potentially type 100% of PorB VR diversity.
Conclusions:
- Oligonucleotide probes provide a simple, rapid, and comprehensive method for N. meningitidis serotyping.
- This technique enhances the characterization of PorB protein diversity.
- The probe-based approach is suitable for analyzing large sample sets.