Relationship of Leishmania-specific IgG levels and IgG avidity with parasite density and clinical signs in canine leishmaniasis.
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).
Teixeira Neto
Rafael Gonçalves
RG
Laboratório de Imunopatologia, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
Giunchetti
Rodolfo Cordeiro
RC
Carneiro
Cláudia Martins
CM
Vitor
Ricardo Wagner de Almeida
RW
Coura-Vital
Wendel
W
Quaresma
Patrícia Flávia
PF
Ker
Henrique Gama
HG
de Melo
Lutiana Amaral
LA
Gontijo
Célia Maria Ferreira
CM
Reis
Alexandre Barbosa
AB
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
D000913:Antibodies, Protozoan; D007074:Immunoglobulin G