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Immunization with major outer membrane protein (porin) preparations in experimental murine salmonellosis: effect of
Abstract:
A crude major outer membrane (porin) preparation, obtained from a rough strain of Salmonella typhimurium earlier shown to be protective both in active and passive immunization of mice against challenge with smooth S. typhimurium, was further purified. Removal of the main impurities, lipopolysaccharide (LPS) and lipoprotein, was accompanied by loss of protective capacity in passive immunization experiments. Reconstitution with rough LPS restored the protective capacity. Protection was, however, concluded not to be due to anti-LPS, because a large fraction of the anti-LPS antibodies could be removed from the protective rabbit antiserum with an LPS immunosorbent without loss of protection.
Insights
Purified Salmonella outer membrane porins lost protective immunity, but rough lipopolysaccharide (LPS) reconstitution restored it. Protection was not due to anti-LPS antibodies, indicating porins
Area of Science:
- Microbiology
- Immunology
- Bacterial Pathogenesis
Background:
- Salmonella typhimurium outer membrane preparations possess protective immunity.
- Rough strains of S. typhimurium are used for immunization studies.
- Outer membrane proteins, including porins, are key targets for immune responses.
Purpose of the Study:
- To investigate the protective role of purified outer membrane (porin) preparations from Salmonella typhimurium.
- To determine the contribution of lipopolysaccharide (LPS) and lipoprotein impurities to the protective capacity of porin preparations.
- To elucidate the mechanism of protection conferred by Salmonella outer membrane components.
Main Methods:
- Purification of major outer membrane (porin) preparation from a rough strain of Salmonella typhimurium.
- Passive immunization experiments in mice using purified and reconstituted preparations.
- Immunoassays to assess antibody removal and its effect on protective capacity.
Main Results:
- Purification of the outer membrane preparation led to a loss of protective capacity in passive immunization.
- Reconstitution of the purified preparation with rough lipopolysaccharide (LPS) restored its protective capacity.
- Removal of anti-LPS antibodies from protective antiserum did not diminish protection, suggesting protection is not LPS-mediated.
Conclusions:
- The protective capacity of the Salmonella outer membrane preparation is linked to its LPS content.
- Protection is not solely mediated by antibodies against LPS.
- Porins or other non-LPS outer membrane components may play a role in the observed protection, potentially in conjunction with LPS.