title: Relationship of Leishmania-specific IgG levels and IgG avidity with parasite density and clinical signs in canine leishmaniasis.
abstract: The clinical status and tissue parasite burden of the skin and spleen of 40 dogs naturally infected with Leishmania chagasi (syn. Leishmania infantum), together with 5 uninfected control dogs, were assessed. On the basis of the clinical evaluation, infected dogs were classified as asymptomatic (AD) or symptomatic (SD). Infected animals were also grouped according to their parasite load as exhibiting low (LP), medium (MP) and high (HP) parasitism. The results indicated a high parasite load in the skin samples of SD animals in relation to the AD group. The serum immunoglobin isotype profiles of the studied animals revealed increased levels of IgG(1) in the AD and LP dogs, whereas high levels of IgG(2) were correlated with SD and HP dogs. The avidity index (AI) of IgG(total) in the SD group was high in comparison of that of the AD group. Moreover, animals with a larger parasite burden either in the spleen or skin showed higher AI values than animals with lower parasitism. Based on these findings, it is suggested that CVL commences with an asymptomatic clinical form with low parasitism, high production of IgG(1) and low affinity of IgG(total) molecules, and evolves into a symptomatic clinical form with higher parasitism intensity, higher IgG(2) levels, and high affinity of IgG(total).
authors.affiliation: Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
authors.forename: Rafael Gonçalves
authors.initials: RG
authors.lastname: Teixeira Neto
authors.forename: Rodolfo Cordeiro
authors.initials: RC
authors.lastname: Giunchetti
authors.forename: Cláudia Martins
authors.initials: CM
authors.lastname: Carneiro
authors.forename: Ricardo Wagner de Almeida
authors.initials: RW
authors.lastname: Vitor
authors.forename: Wendel
authors.initials: W
authors.lastname: Coura-Vital
authors.forename: Patrícia Flávia
authors.initials: PF
authors.lastname: Quaresma
authors.forename: Henrique Gama
authors.initials: HG
authors.lastname: Ker
authors.forename: Lutiana Amaral
authors.initials: LA
authors.lastname: de Melo
authors.forename: Célia Maria Ferreira
authors.initials: CM
authors.lastname: Gontijo
authors.forename: Alexandre Barbosa
authors.initials: AB
authors.lastname: Reis
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology*; D000915:Antibody Affinity; D004283:Dog Diseases / Q000175:diagnosis / Q000276:immunology* / Q000469:parasitology*; D004285:Dogs; D005260:Female; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D007891:Leishmania / Q000276:immunology*; D007896:Leishmaniasis / Q000175:diagnosis / Q000276:immunology / Q000662:veterinary*; D008297:Male; D012867:Skin / Q000276:immunology / Q000469:parasitology; D013154:Spleen / Q000276:immunology / Q000469:parasitology
chemical_list: D000913:Antibodies, Protozoan; D007074:Immunoglobulin G