This is an open-label protocol in up to 15 healthy adults who are BCG-naïve. All participants will receive a total of two doses of BCG, by intradermal injection, approximately 6 months apart. Participants will be followed by a combination of visits and telephone contacts through Study Day 264. Participants will undergo TST testing 3 months after the second BCG vaccination and QuantiFERON TB Gold in-Tube (QTBGT), or the equivalent, if necessary. Two BCG vaccinations given 6 months apart were chosen for this study to give optimal T cell and antibody responses for future study. Leukapheresis will be conducted prior to the first BCG vaccination and at 56 days after the second BCG vaccination (Hoft, 2002; Brown, 2003; de Valliere, 2005). The final leukapheresis timing was selected based on results from functional biological assays, which suggest analysis of samples at this time point may provide insight into the protective immune responses elicited by BCG, and on results of prior clinical trials describing the peak immune responses to BCG (Hoft, 2002; Brown, 2003; de Valliere, 2005). The study will be conducted at a single site in the US (Saint Louis University [SLU]).