title: Detection of Toxoplasma gondii-specific IgA in the aqueous humor of cats.
abstract: Toxoplasma gondii-specific IgA, IgM, and IgG were measured by ELISA in the serum and aqueous humor of 29 client-owned cats with endogenous uveitis and 7 specific-pathogen-free cats tested sequentially for 20 weeks after inoculation with T gondii. Local antibody production in aqueous humor was estimated by multiplying the aqueous humor-to-serum T gondii-specific antibody ratio by the serum-to-aqueous humor total IgG (C value) or calicivirus-specific IgG (CTC value) ratio. Evidence for local production of antibody in aqueous humor was defined as C value greater than 8 or CTC value greater than 1. Toxoplasma gondii-specific IgM CTC values, IgG CTC values, or IgA CTC values greater than 1 were detected in the aqueous humor of 18 of 29 (62.1%) client-owned cats with endogenous uveitis; 2 cats had IgA CTC values greater than 1 without detectable IgM or IgG in aqueous humor. Toxoplasma gondii-specific IgM was not detected in the aqueous humor of experimentally inoculated cats before or after inoculation. Immunoglobulin G C values greater than 8 were detected in all 7 experimentally inoculated cats and ranged from 10.4 to 145.5. Immunoglobulin G C values greater than 8 were first detected 4 to 8 weeks after T gondii inoculation and were undetectable by week 16 after inoculation. Immunoglobulin A C values greater than 8 were detected in 4 of 7 cats and ranged from 12.7 to 264.3. Immunoglobulin A C values greater than 8 were first detected 4 to 8 weeks after inoculation, and were detected in 2 cats during week 20 after inoculation. It was concluded that some cats infected with T gondii develop detectable concentrations of T gondii-specific IgA in aqueous humor.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Lappin
authors.forename: D P
authors.initials: DP
authors.lastname: Burney
authors.forename: S A
authors.initials: SA
authors.lastname: Hill
authors.forename: M J
authors.initials: MJ
authors.lastname: Chavkin
mesh_terms: D000818:Animals; D000917:Antibody Formation; D000953:Antigens, Protozoan / Q000032:analysis*; D001082:Aqueous Humor / Q000276:immunology*; D002371:Cat Diseases; D002415:Cats; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007070:Immunoglobulin A / Q000032:analysis*; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D013997:Time Factors; D014122:Toxoplasma / Q000276:immunology*; D014124:Toxoplasmosis, Animal / Q000276:immunology*; D014126:Toxoplasmosis, Ocular / Q000276:immunology* / Q000662:veterinary
chemical_list: D000953:Antigens, Protozoan; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M