Serum antibody responses of foals to virulence-associated 15- to 17-kilodalton antigens of Rhodococcus equi.
Humoral immune responses in 16 foals to virulence-associated 15- to 17-kDa antigens of Rhodococcus equi were studied during the first fourteen weeks of life on two horse-breeding farms with a persistent incidence of R. equi infection. Serum antibody levels specific for 15- to 17-kDa antigens were measured by enzyme-linked immunosorbent assay and Western immunoblotting. Immunoglobulin G (IgG) antibodies specific to 15- to 17-kDa antigens were detected by all the foals. R. equi was found in the feces of foals during week 1 of life, and the number of fecal R. equi rapidly increased to the highest level. Virulent R. equi were isolated from the feces of the foals at a high frequency and from their environmental soil on the farms. Evidence that serum antibody response to 15- to 17-kDa antigens of virulent R. equi occurred naturally in every foal in correlation with the quantitative changes of fecal R. equi during the first 1 to 3 months of life suggests that intestinal virulent R. equi might be the most important source of antigenic stimulation in foals from contaminated farms.
Tákai
S
S
Department of Animal Hygiene, School of Veterinary Medicine and Animal Sciences, Kitasato University, Aomori, Japan. takai@vmas.kitasato-u.ac.jp
Hidaka
D
D
Fujii
M
M
Shindoh
Y
Y
Murata
T
T
Nakanishi
S
S
Sasaki
Y
Y
Tsubaki
S
S
Kamada
M
M
D000193:Actinomycetales Infections / Q000453:epidemiology / Q000276:immunology / Q000662:veterinary*; D000375:Aging / Q000276:immunology; D000818:Animals; D000831:Animals, Newborn; D000914:Antibodies, Viral / Q000097:blood*; D000917:Antibody Formation; D000956:Antigens, Viral / Q000276:immunology*; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000821:virology; D005260:Female; D006734:Horse Diseases; D006736:Horses; D015994:Incidence; D016929:Rhodococcus equi / Q000276:immunology / Q000472:pathogenicity; D012988:Soil Microbiology; D014774:Virulence
D000914:Antibodies, Viral; D000956:Antigens, Viral