Mechanism of protective immunity induced by porin-lipopolysaccharide against murine salmonellosis.
Investigations were undertaken to characterize the protective immunity induced by porin-lipopolysaccharide (LPS) against Salmonella typhimurium infection in mice. Mice immunized with porin-LPS showed higher levels of antiporin immunoglobulin G than mice which received porin alone. Further, T cells from porin-LPS-immunized mice showed an augmented proliferative response to porin in vitro compared with the response of T cells from porin-injected animals. The passive transfer of anti-LPS antibodies conferred significant protection (17%), while antiporin serum failed to protect mice against lethal challenge, indicating the protective ability of anti-LPS antibodies. However, the transfer of serum obtained from porin-LPS-immunized mice resulted in better protection (30%) than did anti-LPS or antiporin antibodies alone. In contrast to LPS, monophosphoryl lipid A completely failed to induce protection against lethal infection. However, comparable to the effect of LPS, injection of porin with monophosphoryl lipid A enhanced antibody response and the protective ability of porin (81.25%). The transfer of T cells from porin-LPS-immunized mice provided higher levels of protection (47%) against lethal challenge than did T cells from porin-immunized mice (23%). The combination of T cells and serum from porin-immunized mice transferred 36% protection. However, a combination of T cells and serum from porin-LPS-immunized mice conferred the highest level of protection (92%), which was reflected by the number of survivors (100%) in the porin-LPS-immunized group. These results demonstrate that besides the protective effect of anti-LPS antibodies, the ability of LPS to augment humoral and cell-mediated immune responses to porin confers effective protection against Salmonella infection.
Department of Immunology, School of Biological Sciences, Madurai Kamaraj University, India.
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S
Muthukkumar
V R
VR
Muthukkaruppan
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D005260:Female; D007106:Immune Sera / Q000276:immunology; D007114:Immunization; D007116:Immunization, Passive; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008050:Lipid A / Q000031:analogs & derivatives / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000276:immunology* / Q000494:pharmacology; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018272:Porins; D012481:Salmonella Infections, Animal / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D007106:Immune Sera; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008050:Lipid A; D008070:Lipopolysaccharides; D018272:Porins; C048436:monophosphoryl lipid A