DELAYED HYPERSENSITIVITY-INDUCING AND SEROLOGICAL PROPERTIES OF VARIOUS PROTEINS OBTAINED FROM MYCOBACTERIUM-BOVIS

The delayed hypersensitivity-inducing property of ammonium sulphate pr ecipitated protein (ASPP) obtained from culture supermatant of autocla ved culture of Mycobacterium bovis (AN 5) was studied. The ASPP was ei ther directly applied to a DEAE-Sepharose CL-6B (Sigma) column or filt ered through Sepharose G-200 (SRL) containing 2 M urea. The resultant fractions were characterized. Application of ASPP on DEAE-Sepharose re sulted in the elution of RNA in the initial buffer (tris HC1,8.6) wash followed by a protein peak each using 0.2 M NaCl and 0.5 M NaCl in th e eluting buffer. Of these, the peak obtained at 0.2 M NaCl gradient ( ASD I) was the major peak. When ASPP was filtered through Sepharose G- 200 two protein peaks appeared, first the minor one (ASGI) nearly at t he void volume followed by the major peak (ASG II). Only the major pea ks (ASD I,ASG II) were able to inhibit a homologous PHA reaction and p recipitate in gel using anti-M. bovis serum. Delayed hypersensitivity skin response observed in guineapigs using these preparations indicate d higher skin reactive property of ASD I and ASG II. The responses wer e higher in animals sensitized with M. bovis or M. tuberculosis than t hose with M. avium. Similar studies conducted in guineapigs at differe nt intervals after infection with M. bovis or M. chelonei suggested ma ximum sensitivity to ASD I at 30th day of inoculation of the organisms in M. bovis-infected guineapigs only. ASD I was also able to induce a positive skin response in calves sensitized with M. bovis but signifi cantly lower response in the calves sensitized with either M. tubercul osis or M. kansasii. Commercial tuberculin did not exhibit such a diff erence. The results showed that ASD I could be used as a sensitin to e licit specific skin reaction in animals for diagnosing tuberculosis.