CD44 variant–specific antibodies stimulate myelopoiesis and lymphopoiesis.
Myeloid (A,B) or lymphoid (C,D) LTBMCs were grown in the absence or presence of CD44 exon v4-, v6-, or v7-specific antibodies (10 μg/mL). (A,C) Nonadherent cells were harvested weekly during feedings of 3 separate cultures; numbers were counted and expressed as mean ± SD. (B,D) Nonadherent cells harvested from LTBMCs were plated at a concentration of 104 cells/mL in 4 separate methylcellulose cultures supplemented with IL-3. After 7 days in culture, the number of colonies was counted, recalculated for the total number of cells obtained originally from each LTBMC culture well, and expressed as mean number of colonies per LTBMC culture well ± SD. The experiment was repeated 4 times with similar results. (E,F) Nonadherent cells were washed off from myeloid LTBMCs cultured for 5 weeks in the presence or absence of antibodies. The numbers of nonadherent cells were similar to those obtained in A. Adherent cells were harvested (by trypsinization), counted (E), and tested for LTC-ICs in a 2-week limiting dilution assay (F). The data shown are the means (± SD) of 2 experiments.
