The PPD-specific T-cell clonal response in UK and Malawian subjects following BCG vaccination: a new repertoire evolves over 12 months.

Mycobacterium bovis bacille Calmette Guerin vaccination protects against pulmonary tuberculosis in the United Kingdom but not in Malawi. We investigated whether a difference in the clonal T-cell response to BCG vaccination might account for this. The results of clonal analysis were compared to those obtained by skin testing and in a whole blood interferon gamma assay.