T cells are depleted early but also proliferate late in the cultures with mATG. Cultures of C57BL/6 splenocytes with 100 μg/mL mATG or rabbit IgG in the presence of 200 U/mL IL-2 were evaluated for absolute numbers of CD4⁺, CD8⁺, CD19⁺ (B cells), CD3⁺, NK1.1⁺ (NKT cells), or CD3⁻NK1.1⁺ (classic NK cells) or BrdU incorporation into specific cell populations by flow cytometric analysis described in “Methods.” (A) Cell populations at day 1. (B) Cell populations at day 5. (C) BrdU was added to the cultures on day 4 and evaluated the following day for BrdU incorporation into the CD4⁺, CD8⁺ and CD19⁺ cell populations as described in “Methods.” Data shown are means (± standard deviation [SD]) of 3 replicates from a representative of at least 6 separate experiments.