摘要：A new batch of PPD tuberculin, RT 23, prepared at the request of UNICEF by the Statens Seruminstitut, Copenhagen, has been compared with previous batches of tuberculin from the Statens Seruminstitut and with the International Standard for the Purified Protein Derivative of Mammalian Tuberculin. The comparisons were made by intradermal tuberculin testing. The majority of tests were carried out in human subjects with various types and levels of tuberculin sensitivity—namely, tuberculous patients in the Netherlands; BCG-vaccinated as well as spontaneously tuberculin-sensitive army recruits in the Netherlands; BCG-vaccinated schoolchildren in Denmark; population groups in the tropics (Mauritius and Nigeria) including a high proportion of persons with low-grade sensitivity. In addition, comparisons were made in guinea-pigs sensitized in different ways. For these comparisons, RT 23 was diluted both with phosphate-buffered saline alone (as were the other preparations) and with phosphate-buffered saline containing 0.05‰ Tween 80 as a stabilizing agent. The results were found to differe significantly with the type and level of sensitivity of the groups tested. Thus, while the potency ratio of RT 23 and the International Standard is about 2:1 in BCG-vaccinated persons, it is about 1:1 in persons with naturally acquired tuberculin sensitivity. RT 23 in diluent containing Tween 80 elicited larger reactions than did RT 23 in ordinary diluent; however, when reactions of the same size were compared, a difference in character was observed: the reactions to RT 23 diluted with Tween 80 were softer and less frequently bullous. On the basis of the results—in terms of reaction size—obtained in patients and in non-vaccinated recruits, it is suggested that one unit of RT 23 should be defined as 0.02 μg of the dry substance; for use as a first or single dose in routine testing, 0.02 μg of RT 23 in diluent stabilized with Tween 80, or 0.06 μg in diluent without Tween 80, is recommended. Full text Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (6.0M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References . 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951
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