Canine antibody response to Blastomyces dermatitidis WI-1 antigen.
OBJECTIVE
To assess whether dogs with blastomycosis produce antibodies against the WI-1 and A-antigens of Blastomyces dermatitidis and whether the antibodies are useful in serodiagnosis.


METHODS
359 serum samples obtained from 245 dogs.


METHODS
233 samples from 122 dogs with blastomycosis, and 1 sample each from 24 dogs with suspected blastomycosis, 51 control dogs without infection, and 48 healthy dogs from an enzootic region were obtained. Antibodies against WI-1 antigen were detected by radioimmunoassay (RIA). Serum samples were tested in parallel for antibodies against the A-antigen of B dermatitidis by commercial agar-gel immunodiffusion (AGID) in a reference laboratory.


RESULTS
Antibodies were detected in 92% of infected dogs by RIA and in 41 % by AGID. For 29 serum samples that were obtained 11 to 1,545 days after diagnosis, antibodies were detected in 92% of samples by RIA and 7% by AGID. For 93 serial serum samples from 29 dogs with blastomycosis, the mean anti-WI-1 titer was 1:18,761 at the time of diagnosis, and decreased to a mean of 1:1,338 by 210 days after treatment was initiated. Of 24 dogs with suspected infection, antibodies were detected in 67% by RIA and 33% by AGID. Control dogs without blastomycosis had no detectable antibodies in either assay. Thus, sensitivity was 92% for RIA and 41 % for AGID, and specificity was 100% for both tests.


CONCLUSIONS
Anti-WI-1 antibodies are readily detected by RIA in dogs with blastomycosis. Titers become high, decline during treatment, and persist for months. Anti-A antibodies are sometimes detected with AGID, but these decrease quickly.
Klein
B S
BS
Department of Internal Medicine, University of Wisconsin Medical School, Madison 53792, USA.
Squires
R A
RA
Lloyd
J K
JK
Ruge
D R
DR
Legendre
A M
AM
D000818:Animals; D000908:Antibodies, Fungal / Q000096:biosynthesis* / Q000097:blood; D000946:Antigens, Fungal / Q000276:immunology; D001758:Blastomyces / Q000276:immunology* / Q000302:isolation & purification; D001759:Blastomycosis / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D002140:California / Q000453:epidemiology; D004283:Dog Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology; D004285:Dogs; D005656:Fungal Proteins; D006023:Glycoproteins / Q000276:immunology*; D005779:Immunodiffusion / Q000662:veterinary; D011237:Predictive Value of Tests; D011863:Radioimmunoassay / Q000662:veterinary; D012680:Sensitivity and Specificity; D013714:Tennessee / Q000453:epidemiology; D014922:Wisconsin / Q000453:epidemiology
D000908:Antibodies, Fungal; D000946:Antigens, Fungal; D005656:Fungal Proteins; D006023:Glycoproteins