Serum antigen 85 levels in adjunct testing for active mycobacterial infections in orangutans.
Diagnosis of active mycobacterial disease in orangutans (Pongo pygmaeus) has been impeded by high levels of non-specific intradermal skin test reactivity to mycobacterial antigens. This may be due in part to cross reactivity between antigens, tuberculin concentrations used or other species-specific factors. Antigen 85 (Ag85) complex proteins are major secretory products of actively growing mycobacteria, and measurement of serum Ag85 could provide a method for determining active mycobacterial infections that was not dependent on host immunity. Serum Ag85 was measured by dot-immunobinding assay using monoclonal anti-Ag85, purified Ag85 standard and enhanced chemiluminescence technology in coded serum samples from 14 captive orangutans from a zoo in Colorado, 15 semi-captive orangutans in Malaysia, and 19 free-ranging wild orangutans in Malaysia. Orangutans from Colorado (USA) were culture negative for Mycobacterium tuberculosis and M. avium, although all had laboratory suspicion or evidence of mycobacterial infection; median serum Ag85 was 10 microU/ml (range, <0.25-630 microU/ml). Of the semi-captive orangutans, six were skin test reactive and two were culture positive for M. avium on necropsy. Median serum Ag85 for this group was 1,880 microU/ml (0.75-7,000 microU/ml), significantly higher than that of Colorado zoo or free-ranging Malaysian orangutans. Median serum Ag85 in the latter group was 125 microU/ml (range, 0.75-2,500 microU/ml). These data suggest that suggest that additional studies using more specific reagents and more samples from animals of known status are appropriate.
Kilbourn
A M
AM
Wildlife Health Sciences, Wildlife Conservation Society, Bronx, New York 10460, USA.
Godfrey
H P
HP
Cook
R A
RA
Calle
P P
PP
Bosi
E J
EJ
Bentley-Hibbert
S I
SI
Huygen
K
K
Andau
M
M
Ziccardi
M
M
Karesh
W B
WB
D000818:Animals; D000835:Animals, Wild; D000836:Animals, Zoo; D000942:Antigens, Bacterial / Q000032:analysis*; D003120:Colorado; D007118:Immunoassay / Q000379:methods / Q000662:veterinary; D008163:Luminescent Measurements; D008296:Malaysia; D009162:Mycobacterium avium / Q000302:isolation & purification; D009163:Mycobacterium bovis / Q000276:immunology* / Q000302:isolation & purification; D011148:Pongo pygmaeus; D018419:Primate Diseases / Q000276:immunology*; D012882:Skin Tests / Q000662:veterinary; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology
D000942:Antigens, Bacterial; C065036:antigen 85, Mycobacterium bovis