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Kari Fluegel February 3, 1993

Johnson Space Center

(713) 483-5111

Release No. 93-006

STS-55 EXPERIMENT FOCUSES ON LYMPHOCYTE ACTIVATION

The microgravity environment of space is expected to play a significant role in expanding the envelope of biotechnology. Already experiments on NASA's space shuttle have advanced this area of medical science and joint German-American study of immune cells will continue that trend.

During the upcoming German Spacelab mission known as D-2, the Hybri/Doma experiments will explore the effects of weightlessness on manipulating human immune cells or lymphocytes. Researchers at the University of Wurzburg, University of Iowa and University of Arizona will use the experiment to determine if lymphocytes function normally outside the body in a microgravity environment.

Astronauts will activate resting B lymphocytes, the cells which form antibodies and immunity, in order to acheive and maintain optimal cellular viability and responsiveness. Several activation condition will be test in space to evaluate the efficiency of activation in a cultural medium. Crew members then will fuse activated cells with myeloma (cancer) cells, a process which lengthens the hybrid cells life span. Both the hybrids and the activated cells will be analyzed post-flight.

Human spleen cells will be placed into culture compartments under conditions that will maintain a viable but resting state. After launch, crew members will inject an activating agent into the cell compartment. The activating agent will be lipopolysaccharide or T lymphocytes which are known to have a positive affinity for the B lymphocyte cell surface and initiate the activation response. The injection of activating agents into the cell compartment will activate the resting cells to undergo biological changes required for fusion and the secretion of antibodies. Later, some of the activated cells will be used in several procedures.

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One protocol is performed is performed by the astronaut using several intricate instruments in the Spacelab module's experiment workstation. The experiments are monitored by the astronaut through a microscope similar to procedures on Earth. After fusion of the cell to its partner, the biological events occurring inside the cell are stopped by the addition of a fixative solution containing paraformaldehyde. These cells are returned to storage for post-flight analysis.

In another activity, a crew members will remove portions of the sample from the activation cell compartment. Samples that are removed at various times after addition of the activating agents are fixed with paraformaldehyde to stop cellular events.

Upon return to Earth, the fixed samples of cells will be analyzed to document morphological, molecular and cell cycle changes. Researchers also will assess if cell fusion and activation differs between ground and space environment.

These experiments will provide a foundation for future experiments focusing on bioprocessing human cell samples and manipulating the cells outside the body. The data collected from these cell activation studies also will be valuable in planning procedures for emergency space medicine on prolonged space flights.

The initial objective of the experiment was to evaluate the effects of microgravity on the biophysical phenomena involved in electrofusion (the method used to generate hybrid cells) but the development of techniques required for the successful generation of antibody producing hybrid cells with the desirable antibody characteristics also is an important benefit.

This requires isolation of the subpopulation of the B lymphocyte cells with the appropriate "in vivo" experience in the body so they are responsive to "in vitro" manipulation in the laboratory. The American activities related to the experiment have focused on the technology required for the successful activation of the immune cells. Initial studies used mouse lymphocytes, and the resulting ground based findings were used to adapt the methods for human cells experiments.

The flight hardware and experimental procedures were taken from a variety of science fields including biophysics, cell biology and immunology. The immunological cells for the flight experiment and the methods for measuring B

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lymphocyte cell activation status have been developed by Dr, Garry Neil of the University of Iowa and Dr. David Sammons of the University of Arizona. As a result of the pre-flight research, Neil and Sammons have issued nine patent disclosures to their universities resulting thus far in two patents with three more pending. The instrumentation for the experiment has been developed and tested by DARA contractors under the direction of Dr. Ulrich Zimmerman of the University of Wurzberg.

The collaboration is part of an international agreement between NASA and DARA.

 

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