Characterisation of the under-agarose method for quantifying migration of highly purified human monocytes

Optimal conditions governing migration towards chemotactic agent (MTCA) and random migration of purified human monocytes under agarose have been determined. These include an incubation period of 20 h, use of blood group AB pooled human serum, 0.75% agarose type I, pH between 6.8 and 7.2 and performance in 35 mm Falcon plastic petri dishes. A discontinuous Percoll density gradient was used to give monocyte purity of 83 ± 10% and viability 97–99%. The use of highly purified monocytes was found to be essential, as increasing lymphocyte: monocyte ratio caused inhibition of migration.