GROWTH-HORMONE PROMOTES HUMAN T-CELL ADHESION AND MIGRATION TO BOTH HUMAN AND MURINE MATRIX PROTEINS IN-VITRO AND DIRECTLY PROMOTES XENOGENEIC ENGRAFTMENT

Recombinant human growth hormone(rhGH) promotes human T cell engraftme nt in mice with severe combined immunodeficiency, suggesting that rhGH may have effects on T cell adhesion and migration in vivo. The abilit y of rhGH to directly affect the adhesion capacity of human T cells to a variety of human or murine adhesion molecules and extracellular mat rix proteins was examined. rhGH induced significant human T cell adher ence to both human and murine substrates via either beta 1 or beta 2 i ntegrin molecules. rhGH was capable of inducing significant migration of resting and activated human T cells and their subsets. Most of the migratory response to rhGH was chemokinetic rather than chemotactic. I n vivo engraftment studies in severe combined immunodeficiency mice re ceiving human T cells revealed that treatment with rhGH resulted in im proved thymic engraftment, whereas treatment with non-human-reactive o vine GH demonstrated no significant effects. These data demonstrate th at rhGH directly augments human T cell trafficking to peripheral murin e lymphoid tissues. rhGH appears to be capable of directly altering th e adhesive and migratory capacity of human T cells to molecules of eit her murine or human origin. Therefore, GH may, under either isogeneic or xenogeneic conditions, play a role in normal lymphocyte recirculati on.