| Immunology changes in spaceflight | ||
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Early NASA studies demonstrated that the lymphocytes (white blood cells)
had a blunted response to mitogen stimulation of growth. In the late
60’s returning Apollo astronauts were found to have reduced immune
function after spaceflight, taking approximately 7 days to recover normal
function. As seen in the figure below, T-cells in astronauts exposed to microgravity did not
respond to mitogen, while cells belonging to non-flown astronaut backups
had normal response. Later, Dr. Augusto Cogoli
demonstrated that indeed the cells themselves were responsible for the
change, it was not a systemic change. Dr. Cogoli demonstrated changes in the T-cells
during exposure to microgravity. This current program will examine the
expression of IL-2, and the three IL-2 receptor subunits (alpha, beta and
gamma) in microgravity with and without an artificial 1g gravity vector
and compare those results with ground controls. These studies will show
the regulation of the earliest signals that cause the T-cell to activate
and the role of normal earth’s gravity in that signaling. The first steps include antigen binding and secondary recognition signals. Third step is secretion of IL-2. Fourthly, is the synthesis of the three IL-2 receptors and finally the binding of IL-2 to its receptor. These are the steps of activation that will be analyzed using RTPCR for messenger RNA and with western blots for changes in protein synthesis. This laboratory has become interested in the signal pathways that are stimulated early in activation. These include extracellular and intercellular mechanisms. Since all terrestrial life began in a gravity field. The possible pathways involved in
early T-cell activation are shown below. |
activation
are shown to the right. 