title: The heavy chain variable segment gene repertoire in chronic Chagas' heart disease.
abstract: Patients chronically infected with Trypanosoma cruzi develop chronic Chagas' heart disease (cChHD). Their Ab response is suspected to be involved in the cardiac pathogenesis. Reactivity of serum Abs from these patients has been extensively studied but little is known about the diversity of the in vivo IgG repertoire. We analyzed 125 variable H chain (VH) genes and compared it to repertoires from healthy individuals, and patients with autoimmune processes and other infections. VH were from plasma cells isolated from heart tissue of three cChHD patients and from a Fab combinatorial library derived from bone marrow of another cChHD patient. The role of the parasite in shaping the Ab repertoire was assessed analyzing VH genes before and after panning against T. cruzi Ag. Among recovered VH genes, a significantly increased representation of VH4 was observed. Plasma cells at the site of cardiac infiltration showed an increased VH1 usage. CDR3 lengths were similar to the ones found in the healthy repertoire and significantly shorter than in other infections. VH derived from anti-T. cruzi Fab and plasma cells showed a higher proportion of hypermutated genes, 46.9% and 43.75%, respectively, vs 30.9% of the cChHD patient repertoire, pointing to the role of parasite Ags in the shaping of the humoral response in Chagas' disease. No histological evidence of germinal center-like structures was observed in heart tissue. In accordance, VH analysis of heart plasmocytes revealed no evidence of clonal B cell expansion, suggesting that they migrated into heart tissue from secondary lymphoid organs.
authors.affiliation: Laboratory of Molecular Biology of Chagas' Disease, Institute for Genetic Engineering and Molecular Biology, CONICET, Buenos Aires, Argentina.
authors.forename: Vanina
authors.initials: V
authors.lastname: Grippo
authors.forename: Evelyn
authors.initials: E
authors.lastname: Mahler
authors.forename: Fernando E
authors.initials: FE
authors.lastname: Elias
authors.forename: Ana
authors.initials: A
authors.lastname: Cauerhff
authors.forename: Karina A
authors.initials: KA
authors.lastname: Gómez
authors.forename: Maria C
authors.initials: MC
authors.lastname: Tentori
authors.forename: Aurora
authors.initials: A
authors.lastname: Ruiz
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Vigliano
authors.forename: Ruben P
authors.initials: RP
authors.lastname: Laguens
authors.forename: Claudia
authors.initials: C
authors.lastname: Berek
authors.forename: Mariano J
authors.initials: MJ
authors.lastname: Levin
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000913:Antibodies, Protozoan / Q000096:biosynthesis / Q000235:genetics*; D000953:Antigens, Protozoan / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology / Q000469:parasitology / Q000473:pathology; D002598:Chagas Cardiomyopathy / Q000276:immunology* / Q000469:parasitology / Q000473:pathology; D002908:Chronic Disease; D022801:Complementarity Determining Regions / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D015322:Gene Rearrangement, B-Lymphocyte / Q000235:genetics*; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000096:biosynthesis* / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000096:biosynthesis* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D027041:Somatic Hypermutation, Immunoglobulin / Q000235:genetics; D014349:Trypanosoma cruzi / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D022801:Complementarity Determining Regions; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region