T-cell chemotactic activity of cytokine LD78: a comparative study with interleukin-8, a chemotactic factor for the T-cell CD45RA+ phenotype.

The recombinant LD78 cytokine (rLD78) promoted migration of human peripheral T lymphocytes at concentrations from 10(-11) M to 10(-7) M, with a peak of activity at 10(-8) M. There was no difference in migration promoting activity between LD78 alpha and its variant LD78 beta. Checkerboard analysis indicated that the migration of T cells attracted by rLD78 was chemotaxis but not chemokinesis. The chemotactic activity of rLD78 was apparently ten-fold lower than that of recombinant inteleukin-8 (rIL-8) when peripheral T cells were used as the indicator cells. Subset analysis on T cells responding to rLD78 or rIL-8 indicated that rIL-8 was more chemotactic for the CD45RA+ T cell subset than the CD45RO+ subset, but did not distinguish between CD4+ and CD8+ T cell subsets. In contrast, rLD78 apparently distinguished neither between CD4+ and CD8+ T cell subsets nor between CD45RA+ and CD45RO+ subsets.