title: Immune response against M protein-conserved region peptides from prevalent group A Streptococcus in a North Indian population.
abstract: BACKGROUND
  Group A streptococci (GAS) cause infections with a high prevalence in most developing countries. A GAS vaccine under trial that is based on the amino-terminus of the M protein provides type-specific immunity, and hence seems ineffective in India because of heterogeneous emm types. However, the conserved C-terminal region of the M protein protects against multiple serotypes. In this paper, the immune response generated against the conserved C-repeat region of the M protein was checked in an Indian population to establish their vaccine candidature.
  
  
  METHODS
  When screened for GAS, patients with pharyngitis, rheumatic fever/rheumatic heart disease (RF/RHD), and invasive disease showed heterogeneous emm types, out of which five prevalent types (1-2, 11, 49, 75 and 112) were selected for the study. The C-terminal region of their M proteins showed conserved C1-, C2-, and C3-repeats. The C1-repeat was more diverse and had two different J14-like sequences. Peptides to these C-terminal regions (J14.1 and J14-R6) were designed. Antibodies against these peptides were analyzed using the sera of 130 GAS-infected volunteers.
  
  
  RESULTS
  Serum antibodies were significantly higher in patients with acute rheumatic fever, RHD, and invasive disease than in patients with pharyngitis or the healthy controls. The serum antibodies to these peptides was higher in teenagers and adults than in children.
  
  
  CONCLUSIONS
  Results showed an association between streptococcal disease progression and the age-related development of immunity to the conserved regions. Hence, these peptides could be considered protective in impeding streptococcal infections worldwide.
authors.affiliation: Department of Experimental Medicine and Biotechnology, Chandigarh, India.
authors.forename: Varun K
authors.initials: VK
authors.lastname: Gupta
authors.affiliation: School of Public Health, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Sasank
authors.initials: S
authors.lastname: Sekhar
authors.affiliation: Department of Experimental Medicine and Biotechnology, Chandigarh, India.
authors.forename: Vanita
authors.initials: V
authors.lastname: Dhanda
authors.affiliation: School of Public Health, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Devinder
authors.initials: D
authors.lastname: Toor
authors.affiliation: School of Public Health, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Department of Experimental Medicine and Biotechnology, Chandigarh, India. Electronic address: superoxide14@gmail.com.
authors.forename: Anuradha
authors.initials: A
authors.lastname: Chakraborti
mesh_terms: D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood* / Q000276:immunology*; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology*; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007194:India; D007223:Infant; D010612:Pharyngitis / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D017434:Protein Structure, Tertiary; D012213:Rheumatic Fever / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D012214:Rheumatic Heart Disease / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D013290:Streptococcal Infections / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D022541:Streptococcal Vaccines / Q000276:immunology*; D013297:Streptococcus pyogenes / Q000276:immunology*; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D022541:Streptococcal Vaccines; C014689:streptococcal M protein
keywords: J14-like sequence; M protein-conserved C region; group A streptococci; immune response