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Histochemical demonstration of neuraminidase effects in pneumococcal meningitis
Abstract:
In three cases of pneumococcal meningitis the in vivo action of pneumococcal neuraminidase could be demonstrated. The removal of sialic acid was demonstrated in necrospy material by the use of labeled peanut agglutinin, which has a high specific affinity for the subterminal disaccharide beta-D-galactopyranosyl-(1-3)N-acetyl-D-galactosamine, thereby exposed. Furthermore, this lectin was used for a rapid in vitro histochemical assay of neuraminidase activity in cerebrospinal fluid and culture medium taken from these cases. From the clinical point of view the exposure of the disaccharide which represents the immunodominant group of the Thomsen-Friedenreich antigen may induce immunologic reactions, because all human sera contain antibodies to this cryptic antigen. Thereby, neuraminidase can contribute to the poor prognosis of pneumococcal meningitis.
Insights
Pneumococcal neuraminidase removes sialic acid in meningitis, exposing an antigen that may trigger immune reactions. This enzyme
Area of Science:
- Microbiology
- Immunology
- Neurology
Background:
- Pneumococcal meningitis is a serious infection with a significant impact on prognosis.
- The role of bacterial enzymes, such as neuraminidase, in disease pathogenesis is an area of ongoing research.
- Sialic acid residues on host tissues can be targets for microbial enzymes.
Purpose of the Study:
- To demonstrate the in vivo action of pneumococcal neuraminidase in cases of pneumococcal meningitis.
- To investigate the clinical implications of neuraminidase activity in this condition.
Main Methods:
- Demonstration of sialic acid removal in necropsy material using labeled peanut agglutinin.
- Development and application of an in vitro histochemical assay for neuraminidase activity in cerebrospinal fluid and culture medium.
Main Results:
- In vivo action of pneumococcal neuraminidase was confirmed in three cases of meningitis.
- Peanut agglutinin binding confirmed the exposure of a specific subterminal disaccharide after sialic acid removal.
- Neuraminidase activity was detected in cerebrospinal fluid and culture samples.
Conclusions:
- Pneumococcal neuraminidase activity leads to the exposure of the Thomsen-Friedenreich antigen's immunodominant group.
- This exposed antigen can elicit immune responses due to pre-existing antibodies in human sera.
- Neuraminidase may contribute to the poor prognosis associated with pneumococcal meningitis.