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Isolation of tuberculin peptides from tuberculin purified protein derivative (PPD)
Abstract:
Tuberculin purified protein derivative (PPD) obtained from the filtrate of Mycobacterium tuberculosis was hydrolysed with proteinase, trypsin, or chymotrypsin. Each hydrolysate consisted of a tuberculin peptides mixture (TPM). From each TPM 16 fractions were obtained by ion-exchange chromatography on Dowex 50W-X8 but only one fraction was isolated from each of the 16 fractions which showed tuberculin activity in guinea pigs sensitized with M. bovis (bcg) or M. tuberculosis. This fraction was designated "purified tuberculin peptide" (PTP). The PTP fraction from the proteinase hydrolysate (PTP-proteinase) was rechromatographed on Dowex 1-X2 and two tuberculin peptide fractions having molecular weights of 3200 and 12,000 were isolated. The potency of these two fractions was assessed in guinea pigs sensitized with M. bovis (BCG) and with M. tuberculosis and they were approximately 4 to 7 times more potent than either the international standaCG and of at least equal potency to either PPD-S or Connaught PPD in guinea pigs sensitized with either M. kansasii, M. scrofulaceum, M. intracellulare, or M. avium whereas very little if any cross-reactivity was elicited by these two fractions. This lack of response indicates that either fraction could be used as an aid to differentiate between sensitization due to M. tuberculosis or M. bovis and sensitization attributed to other mycobacteria.
Insights
Researchers developed purified tuberculin peptides (PTPs) from Mycobacterium tuberculosis. These PTPs show higher potency and can differentiate tuberculosis infections from other mycobacterial exposures.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Tuberculin purified protein derivative (PPD) is derived from Mycobacterium tuberculosis filtrate.
- PPD is used in tuberculin skin tests to diagnose tuberculosis.
- Existing PPD preparations may lack specificity in differentiating mycobacterial infections.
Purpose of the Study:
- To isolate and characterize highly potent tuberculin peptides from PPD.
- To evaluate the diagnostic potential of these purified tuberculin peptides (PTPs) in differentiating Mycobacterium tuberculosis/bovis sensitization from other mycobacteria.
Main Methods:
- Hydrolysis of PPD using proteinase, trypsin, or chymotrypsin.
- Isolation of tuberculin peptides mixture (TPM) and subsequent fractionation using ion-exchange chromatography (Dowex 50W-X8 and Dowex 1-X2).
- Assessment of tuberculin activity and potency in guinea pigs sensitized with various mycobacterial species.
Main Results:
- Purified tuberculin peptides (PTPs) were isolated with molecular weights of 3200 and 12,000.
- PTPs demonstrated 4-7 times higher potency than international standards in sensitized guinea pigs.
- PTPs showed minimal cross-reactivity with other mycobacteria, unlike standard PPD.
Conclusions:
- The isolated PTPs are significantly more potent than current tuberculin preparations.
- These PTPs hold promise as diagnostic aids for distinguishing Mycobacterium tuberculosis/bovis infections from other mycobacterial sensitizations.
- Further research may lead to improved diagnostic tools for tuberculosis.