title: Cross-neutralization of staphylococcal and streptococcal pyrogenic toxins by monoclonal and polyclonal antibodies.
abstract: We evaluated cross-reactivity of antibodies against staphylococcal and streptococcal pyrogenic toxins. Monoclonal antibodies against staphylococcal enterotoxin (ET) C1 and streptococcal pyrogenic exotoxin (SPE) A were tested for reactivity with homologous and heterologous pyrogenic toxins in vitro. Ten immunoglobulin G1 anti-ET C1 monoclonal antibodies showed little or no cross-reactivity in an enzyme-linked immunosorbent assay, but many of these could neutralize the mitogenic effect of ET B, SPE A, or both. Two immunoglobulin M anti-ET C1 monoclonal antibodies and eight immunoglobulin M anti-SPE A monoclonal antibodies showed extensive cross-reactivity in the enzyme-linked immunosorbent assay and the mitogenicity neutralization assay. No cross-reactivity was observed with SPE C or toxic shock syndrome toxin 1. Rabbits immunized against ET B, ET C1, or SPE A were resistant to challenge with the immunizing toxin. In addition, reciprocal immunity was stimulated by the two ETs, and immunity to SPE A provided protection against ET B but not ET C1. These results show that staphylococcal and streptococcal pyrogenic toxins which share sequence homology have common antigenic determinants which may not be detected in Ouchterlony immunodiffusion assays.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001427:Bacterial Toxins / Q000276:immunology*; D000939:Epitopes; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D009500:Neutralization Tests; D011749:Pyrogens / Q000276:immunology*; D011817:Rabbits; D013210:Staphylococcus / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D001427:Bacterial Toxins; D000939:Epitopes; D011749:Pyrogens