Abstract
Summary
A carbohydrate fraction of unheated BCG culture nitrates (GA) known to give equal tuberculin reactivity with PPD in BCG-sensitized guinea pigs was compared to PPD in clinical testing in human subjects. There were no immediate reactions to GA and no “false positives” in PPD negative individuals. PPD positive persons without active tuberculosis were generally unreactive to GA as were patients with active tuberculosis. The only significantly positive reaction was seen in a patient with active tuberculosis whose PPD response was 10-fold greater at the same dose level. Reasons for the unreactivity of humans to BCG polysaccharide despite well-developed PPD sensitivity are discussed.
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