Evaluation of factors affecting the biological activity and stability of different tuberculins [electronic resource].

Includes references.

Tuberculin is widely used antigen for diagnosis of tuberculosis all over the world till present. Wide heterogeneity was shown among different batches (as regards durability, stability and potency) of different PPD tuberculin. These features were investigated in different batches at different dates of mammalian, bovine and avian tuberculin. The results showed that till 15 months of production, no significant difference in both potency (as measured by delayed type hypersensitivity reaction- DTH) and protein content (as measured by micro - Kjeldahl method).A slight drop in the protein concentration was seen after 21 months yet it was non significant.The potency and stability of the mammalian and bovine tuberculin showed a slight decrease after21 months of production (8 - 13 mm) and for the avian tuberculin the potency decreased (5 - 8 mm afterword). Regarding the phenol concentration, a significant decrease in its concentration was noticed after 21 months of production. It was noticed also that air exposed tuberculin results in dramatic decrease in the phenol concentration from 0.5 to 0.35 mg/ml within 4 weeks and subsequent decrease in the skin reaction from 6 - 8 mm. In conclusion, under optimum storage condition all tested tuberculin were stable and potent up to 15 months whereas open tuberculin vials have only 4 weeks of stability.

Summary in Arabic.

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