02495nas a2200361   4500000000100000008004100001260001300042653002600055653002500081653003100106653003800137653002000175653001300195653001100208653003500219653001200254653002500266653002500291653002100316653002500337653001300362653002000375653002500395100001400420700001100434700001700445700001500462245010100477300001000578490000700588520152400595022001402119       1995                            d  c1995 Feb10aAntibodies, Bacterial10aAntibody Specificity10aAntigen-Antibody Reactions10aEnzyme-Linked Immunosorbent Assay10aEpitope Mapping10aEpitopes10aHumans10aImmunoglobulin Class Switching10aleprosy10aLeprosy, lepromatous10aLeprosy, Tuberculoid10aMolecular Weight10aMycobacterium leprae10aPeptides10aProtein Binding10aRecombinant Proteins1 aHussain R1 aMenz B1 aDockrell H M1 aChiang T J00aRecognition of Mycobacterium leprae recombinant 18,000 MW epitopes by IgG subclasses in leprosy.  a290-70 v843 a<p>IgG subclasses are known to be differentially regulated by cytokines (elaborated by activated T cells), which act as growth factors and immunoglobulin switch factors on B cells. In leprosy, we have previously shown that IgG subclass antibodies to a purified recombinant antigen of Mycobacterium leprae (18,000 MW) are restricted to IgG1 and IgG3 across the disease spectrum. The only significant difference observed was that lepromatous patients with low to undetectable T-cell responses showed a strong correlation between IgG1 and IgG3 (P < 0.001) antibodies while tuberculoid patients who showed strong T-cell responses did not show such a correlation. To examine if these differences were related to T-cell-mediated class switching in tuberculoid leprosy patients, we have studied epitope recognition by IgG1 and IgG3 using a panel of synthetic peptides spanning the 18,000 MW molecule in an enzyme-linked immunosorbent assay (ELISA). In lepromatous patients there was little similarity in peptide recognition by IgG1 and IgG3, with IgG1 recognition being restricted to a single dominant carboxy-terminal peptide while the IgG3 antibodies recognized a diverse set of peptides in the N-terminal half of the 18,000 MW molecule. In tuberculoid patients both IgG1 and IgG3 antibody showed recognition of similar peptides in the N-terminal half of the 18,000 MW molecule. Our results therefore support the hypothesis that immunoglobulin class switching is occurring in tuberculoid but not in lepromatous patients.</p>  a0019-2805