Phytohemagglutinin effects on cultured human neural crest tumors

Two human melanoma lines, RPMI-7931 and HS-294, respond to mitogenic stimulation by PHA. A dose-response curve for these lines can be demonstrated with maximal stimulation at 16 and 32 micrograms per ml and inhibition at 75 to 250 micrograms per ml PHA. The mitogenic effects of PHA were inhibited by N-acetyl-D-galactosamine. Neuroblastoma cells also exhibits a similar but less important dose-response to PHA. These data indicate that human melanomas and neuroblastomas may have PHA receptors or mechanisms for mitogenic stimulation which are analogous to those observed with normal lymphocytes.