Antibodies raised in animals against the Streptococcus agalactiae proteins c alpha and R4 and normal human serum antibodies target distinct epitopes.
The targets for normal human serum antibodies that react with proteins c(alpha) and R4 isolated from group B streptococci (GBS; Streptococcus agalactiae) have been studied and compared with the targets for murine monoclonal and rabbit polyclonal antibodies raised against these proteins. The proteins were extracted by trypsin digestion and purified by precipitations and gel filtration and testing was based on enzyme immunoassays. The immune antibodies showed specificity for the corresponding protein, targeted that protein in Western blotting and recognized their targets after heat treatment (100 degrees C) of the proteins. Human antibodies in a commercial gammaglobulin preparation targeted a site(s) common to c(alpha) and R4. This target failed to bind the antibodies in Western blotting and was destroyed by heating. c(alpha)- and R4-reactive antibodies in sera from healthy pregnant women recognized the common, heat-labile determinant(s), but contained little or no antibodies against the heat-stable c(alpha)- or R4-specific determinants. These results are consistent with the notions that (i) the normal human antibodies and the immunization-induced animal antibodies targeted different sites on the c(alpha) and R4 proteins and that (ii) the natural human antibodies targeted conformational epitopes and the immune antibodies targeted linear epitopes. These findings are important for further clarification of GBS immunology and immunoprotection in humans.
Department of Medical Microbiology, Faculty of Medicine, University of Zimbabwe Medical School, PO Box A178, Avondale, Harare, Zimbabwe 2Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, N-7006 Trondheim, Norway.
Sylvester R
SR
Moyo
Department of Medical Microbiology, Faculty of Medicine, University of Zimbabwe Medical School, PO Box A178, Avondale, Harare, Zimbabwe 2Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, N-7006 Trondheim, Norway.
Johan A
JA
Maeland
D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000097:blood / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009664:Norway; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000276:immunology; D011489:Protein Denaturation; D011817:Rabbits; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013290:Streptococcal Infections / Q000276:immunology; D013292:Streptococcus agalactiae / Q000276:immunology*; D015030:Zimbabwe
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D000939:Epitopes; D007106:Immune Sera; D012967:Sodium Dodecyl Sulfate