title: Intestinal antilectin immunoglobulin A antibody response and immunity to Entamoeba dispar infection following cure of amebic liver abscess.
abstract: We followed 93 subjects with amebic liver abscess (ALA) and 963 close associate controls at 3-month intervals for 36 months to characterize intestinal and humoral antibody responses to the amebic galactose-inhibitable lectin and to determine whether immunity developed to Entamoeba histolytica or Entamoeba dispar infection following cure of ALA. We found that ALA subjects had a higher prevalence and level of intestinal antilectin immunoglobulin A (IgA) and serum anti-LC3 (cysteine-rich recombinant lectin protein) IgA and IgG antibodies, P < 0.01 and P < 0.05, respectively, compared to controls. The intestinal antilectin IgA antibody response was sustained over a longer time period in ALA subjects (71.8% remained positive at 18 months and 52.6% at 36 months, P < 0.001 compared to 17.6% and 10.3% of controls, respectively). ALA subjects were highly immune to E. dispar infection throughout the study (0% infected at 6 and 36 months, compared to 6.5% and 4.9% of control subjects, respectively, P < 0.05). Upon entry into the study, 6.3% of ALA subjects were infected with E. histolytica; the incidence of new E. histolytica infections in controls (as determined by culture) was too low (1.4%) to determine whether ALA subjects exhibited immunity to new infections. We found that stool cultures every 3 months markedly underestimated the occurrence of new E. histolytica infections, as 15.3% of controls seroconverted after 12 months of follow-up. Unfortunately, under the field conditions present in Durban, South Africa, enzyme-linked immunosorbent assay for detection of lectin antigen in stool yielded unreliable results. In summary, subjects cured of ALA exhibited sustained mucosal IgA antibody responses to the amebic galactose-inhibitable lectin and a high level of immunity to E. dispar infection. Determination of immunity to E. histolytica following cure of ALA will require the use of more sensitive and reliable diagnostic methods.
authors.affiliation: Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA. ravdi0001@umn.edu
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Ravdin
authors.forename: Mohamed D
authors.initials: MD
authors.lastname: Abd-Alla
authors.forename: Seth L
authors.initials: SL
authors.lastname: Welles
authors.forename: Selvan
authors.initials: S
authors.lastname: Reddy
authors.forename: Terry F H G
authors.initials: TF
authors.lastname: Jackson
mesh_terms: D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D015331:Cohort Studies; D004747:Entamoeba / Q000276:immunology*; D004748:Entamoeba histolytica / Q000276:immunology; D004749:Entamoebiasis / Q000453:epidemiology / Q000276:immunology* / Q000469:parasitology; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000032:analysis* / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007422:Intestines / Q000276:immunology*; D037102:Lectins / Q000276:immunology; D008101:Liver Abscess, Amebic / Q000628:therapy*; D008297:Male; D008562:Membrane Glycoproteins / Q000276:immunology; D011446:Prospective Studies; D015800:Protozoan Proteins / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D007071:Immunoglobulin A, Secretory; D007074:Immunoglobulin G; D037102:Lectins; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; C052452:galactose inhibitable adherence protein, Entamoeba histolytica