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Mitogenic signal transduction in Tlymphocytes in microgravity
Author(s) -
Cogoli Augusto,
Bechler Birgitt,
CogoliGreuter Marianne,
Criswell Sue B.,
Joller Helen,
Joller Peter,
Hunzinger Elisabeth,
Muller Otfried
Publication year - 1993
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.53.5.569
Subject(s) - concanavalin a , microbiology and biotechnology , biology , microcarrier , secretion , receptor , monocyte , signal transduction , cell , immunology , in vitro , endocrinology , biochemistry
Abstract The activation by concanavalin A Con A of human peripheral blood lymphocytes (PBLs) in the presence of monocytes as accessory cells was investigated in cultures exposed to microgravity conditions in Spacelab. Activation of T cells was measured as incorporation of [ 3 H] thymidine into DNA, secretion of interleukin‐2 (IL‐2), and interferon‐7, and expression of IL‐2 receptors. Whereas, as discovered in earlier experiments, the activation of resuspended T cells is strongly inhibited, activation of cells attached to microcarrier beads is more than doubled in microgravity. The results suggest that the depression of the activation in resuspended cells may be attributed to a malfunction of monocytes acting as accessory cells. In fact, although the ultrastructure of resuspended monocytes is not altered in microgravity, the secretion of IL‐1 is strongly inhibited. Our data suggest that (1) IL‐2 is produced independently of IL‐1, (2) IL‐1 production is triggered only when monocytes (and lymphocytes?) adhere to microcarriers, (3) the expression of IL‐2 receptors depends on IL‐1, and (4) provided sufficient IL‐1 is available, activation is enhanced in microgravity. Finally, cultures of resuspended PBLs and monocytes in microgravity constitute a complete and natural system in which monocytes are not operational. This may be useful for studies of the role of accessory cells and cell‐cell interactions in T lymphocyte activation.