Differences in the fibronectin-dependence of migrating cell populations.

In avian embryos, the migration behaviour of several cell populations, melanoblasts, Schwann cells, myogenic cells and axons after application of antibodies directed against the cell-attachment fragment of fibronectin (alpha-CAF) was investigated. The migration of the different cell types was influenced in different ways. 1. Epidermal melanoblasts did not colonize areas into which the antibody had been injected, i.e. distal to the grafting site. They frequently spread proximally to the back and neck, sometimes even as far as to the ipsilateral leg. When grafted to the dorsal side of the wing bud, melanoblasts never spread to the ventral side after injection of the antibody. Non-epidermal melanoblasts continued to migrate distally. 2. Grafted Schwann cells and host axons were not noticeably affected by the antibody injections. Both were found proximally and far distally to the grafting site, i.e. also within the injected area. 3. Myogenic cells were immobilized near the grafting site, where they differentiated biochemically, but sometimes only partially underwent fusion into myotubes. They participated in the formation of host muscle blastemas only immediately adjacent to the non-migratory cell population of the graft such as fibroblasts and cartilage. 4. The injected antibody could be localized up to 5 h after the application in the distal third of the limb bud. We conclude that migrating cell populations show differences in their fibronectin-dependence which probably reflect their use of fibronectin during migration.