Reversal of Chemotaxis in vitro and Chemotactic Activity of Leukocyte Fractions.

Using Boyden'sin vitro method, it was demonstrated that rabbit polymorpho-nuclear leukocytes reversed their direction of migration in response to a concentration gradient of chemotactic serum. The presence of a chemotactic factor or factors associated with the lysosomal fraction of leukocytes which does not require fresh serum for its activity was shown.