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Variation in class 5 protein expression by serogroup A meningococci during a meningitis epidemic
Abstract:
Serogroup A meningococci were isolated from patients and healthy carriers in The Gambia between 1982 and 1988. The class 5 proteins expressed by these bacteria were identified by electrophoretic migration and by serologic tests. Three protein serologic groupings (seroclasses) called A (protein 5a), B (proteins 5b, 5d, or 5e), and C (protein 5c or 5C) were found among 331 bacterial isolates. The number of class 5 proteins expressed per isolate varied from none to four, with a median of two. The class 5 protein composition differed for certain paired isolates obtained from the nasopharynx, blood, and cerebrospinal fluid of diseased patients and for certain pairs of sequential isolates from the nasopharynx of healthy carriers; the medical relevance of this variation remains unclear, although the 5C protein was preferentially isolated from the nasopharynx and the 5a protein from diseased patients. The data show that a large proportion of healthy carriers in The Gambia were exposed to bacteria expressing each of the three seroclasses and that many people were exposed to bacteria expressing each of the three seroclasses and that many people were exposed to two or all three seroclasses during the epidemic of 1982-1983.
Insights
Serogroup A meningococci in The Gambia exhibited diverse class 5 protein expressions. Most healthy carriers were exposed to multiple seroclasses during the 1982-1983 epidemic.
Area of Science:
- Microbiology
- Immunology
- Epidemiology
Background:
- Serogroup A meningococci are a significant cause of bacterial meningitis.
- Understanding protein expression diversity is crucial for vaccine development and disease control.
Purpose of the Study:
- To characterize the class 5 protein expression of Serogroup A meningococci in The Gambia.
- To investigate variations in protein expression between clinical and carrier isolates.
Main Methods:
- Isolation and characterization of Serogroup A meningococci from patients and healthy carriers (1982-1988).
- Identification of class 5 proteins using electrophoretic migration and serologic tests.
- Analysis of protein serologic groupings (seroclasses) and protein composition per isolate.
Main Results:
- Three seroclasses (A, B, C) were identified among 331 isolates.
- Isolates expressed zero to four class 5 proteins, with a median of two.
- Variations in protein composition were observed in paired isolates from patients and carriers; 5C protein was more common in nasopharyngeal isolates, and 5a in diseased patients.
Conclusions:
- A significant proportion of healthy carriers were exposed to multiple seroclasses.
- Widespread exposure to diverse Serogroup A meningococci seroclasses occurred during the 1982-1983 epidemic.
- The clinical relevance of class 5 protein variation requires further investigation.