title: Type-specific antibodies to purified streptococcal M proteins from potentially rheumatogenic M-types in patients with rheumatic fever and rheumatic heart disease.
abstract: This study was designed to identify the predominant serotypes of group A streptococci (GAS) responsible for rheumatic fever (RF) and rheumatic heart disease (RHD) in India. RF and RHD sera were screened for antibodies to M proteins retrospectively against known rheumatogenic M types and M types isolated from patients with acute RF. All GAS strains isolated from four patients with acute RF in a short outbreak of RF, were identical - serum opacity factor (SOF) negative, T-pattern 3/13 B3264 and M-non-typable. Because of this, M protein was isolated from only one of these four M-non-typable strain (S-399). This was done by limited pepsin digestion and purification by ion-exchange chromatography on DEAE-Sephadex, followed by gel filtration. Purified M protein was found to be homologous on SDS-PAGE (mol.wt 20 kDa), immunogenic in rabbits and to retain its antigenic structure. This purified M protein from an M-non-typable strain (pep-MNT) was used as an antigen to screen RF and RHD sera retrospectively by ELISA for the prevalence of the M-non-typable GAS strain. The prevalence of the M-non-typable strain was compared with that of the known rheumatogenic M types. Results suggest that the M-non-typable strain could be a provisional new rheumatogenic M type in India and could be a candidate for a multivalent M-protein vaccine to control RF and RHD.
authors.affiliation: Department of Microbiology, Lady Hardinge Medical School, New Delhi, India.
authors.forename: A
authors.initials: A
authors.lastname: Thakur
authors.forename: S
authors.initials: S
authors.lastname: Singhal
authors.forename: K
authors.initials: K
authors.lastname: Prakash
mesh_terms: D000293:Adolescent; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000276:immunology* / Q000302:isolation & purification; D002352:Carrier Proteins; D002648:Child; D002675:Child, Preschool; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D009895:Opsonin Proteins / Q000276:immunology; D011817:Rabbits; D012189:Retrospective Studies; D012213:Rheumatic Fever / Q000276:immunology / Q000382:microbiology*; D012214:Rheumatic Heart Disease / Q000276:immunology / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D009895:Opsonin Proteins; C014689:streptococcal M protein