Time-course of CD43-stimulated PYK-2 activity in NK cells. (A) NK cells were either plated on dishes coated with BSA (BSA), HP 2/9 anti-CD44 MoAb (-CD44), and anti-CD43 MoAb TP1/36 (-CD43) or plated on dishes coated with BSA and stimulated with soluble anti-CD43 MoAb (soluble -CD43). The cells were allowed to adhere for the indicated times and lysed. Lysates were incubated with the C-19 antibody to immunoprecipitate PYK-2 and activities in the resulting immunoprecipitates were measured by in vitro kinase reactions, as described in Materials and Methods. A representative experiment of 3 is shown. (B) Quantification by densitometric scanning of the effect of stimulation with anti-CD43 on PYK-2 activity. PYK-2 was immunoprecipitated with the C-19 antibody and in vitro kinase reactions performed as described in Materials and Methods. (s) -CD43 indicates soluble antibody. Values are the mean ± SE of 3 independent experiments and are expressed as fold-stimulation above control.