Search NASA⌕ Search

SEARCH · Search NASA

Results for “Immunophenotyping”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

18 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

Comprehensive Astronaut Immune Assessment Following a Short-Duration Space Flight

Immune system dysregulation has been demonstrated to occur during spaceflight and has the potential to cause serious health risks to crewmembers participating in exploration class missions. As a part of an ongoing NASA flight experiment assessing viral immunity (DSO-500), a generalized immune assessment was performed on 3 crewmembers who participated in the recent STS-114 Space Shuttle mission. The following assays were performed: (1) comprehensive immunophenotype analysis; (2) T cell function/intracellular cytokine profiles; (4) secreted Th1/Th2 cytokine profiles via cytometric bead array. Immunophenotype analysis included a leukocyte differential, lymphocyte subsets, T cell subsets, cytotoxic/effector CD8+ T cells, memory/naive T cell subsets and constitutively activated T cells. Study timepoints were L-180, L-65, L-10, R+0, R+3 and R+14. Detailed data are presented in the poster text. As expected from a limited number of human subjects, data tended to vary with respect to most parameters. Specific post-flight alterations were as follows (subject number in parentheses): Granulocytosis (2/3), reduced NK cells (3/3), elevated CD4/CD8 ratio (3/3), general CD8+ phenotype shift to a less differentiated phenotype (3/3), elevated levels of memory CD4+ T cells (3/3), loss of L-selectin on T cell subsets (3/3), increased levels of activated T cells (2/3), reduced IL-2 producing T cell subsets (3/3), levels of IFNg producing T cells were unchanged. CD8+ T cell expression of the CD69 activation markers following whole blood stimulation with SEA+SEB were dramatically reduced postflight (3/3), whereas other T cell function assessments were largely unchanged. Cytometric bead array assessment of secreted T cell cytokines was performed, following whole blood stimulation with either CD3/CD28 antibodies or PMA+ionomycin for 48 hours. Specific cytokines assessed were IFNg, TNFa, IL-2, IL-4, IL-5, IL-10. Following CD3/CD28 stimulation, all three crewmembers had a mission-associated reduction in the levels of secreted IFNg. One crewmember had a post-flight inversion in the IFNg/IL-10 ratio postflight, which trended back to baseline by R+14. Detailed cytokine data are presented in the poster text. This testing regimen was designed to correlate immunophenotype changes (thought to correspond to specific in-vivo immune responses or pathogenesis), against altered leukocyte function and cytokine profiles. In-flight studies are required to determine if post-flight alterations are reflective of the in-flight condition, or are a response to landing and readaptation.

Crucian, Brian↗
NASA NTRS2010

Growing B Lymphocytes in a Three-Dimensional Culture System

A three-dimensional (3D) culture system for growing long-lived B lymphocytes has been invented. The capabilities afforded by the system can be expected to expand the range of options for immunological research and related activities, including testing of immunogenicity of vaccine candidates in vitro, generation of human monoclonal antibodies, and immunotherapy. Mature lymphocytes, which are the effectors of adaptive immune responses in vertebrates, are extremely susceptible to apoptotic death, and depend on continuous reception of survival-inducing stimulation (in the forms of cytokines, cell-to-cell contacts, and antigen receptor signaling) from the microenvironment. For this reason, efforts to develop systems for long-term culture of functional, non-transformed and non-activated mature lymphocytes have been unsuccessful until now. The bone-marrow microenvironment supports the growth and differentiation of many hematopoietic lineages, in addition to B-lymphocytes. Primary bone-marrow cell cultures designed to promote the development of specific cell types in vitro are highly desirable experimental systems, amenable to manipulation under controlled conditions. However, the dynamic and complex network of stromal cells and insoluble matrix proteins is disrupted in prior plate- and flask-based culture systems, wherein the microenvironments have a predominantly two-dimensional (2D) character. In 2D bone-marrow cultures, normal B-lymphoid cells become progressively skewed toward precursor B-cell populations that do not retain a normal immunophenotype, and such mature B-lymphocytes as those harvested from the spleen or lymph nodes do not survive beyond several days ex vivo in the absence of mitogenic stimulation. The present 3D culture system is a bioreactor that contains highly porous artificial scaffolding that supports the long-term culture of bone marrow, spleen, and lymph-node samples. In this system, unlike in 2D culture systems, B-cell subpopulations developing within 3D cultures that have been modified to foster lymphopoiesis retain an immunophenotype that closely recapitulates cells in fresh bone marrow harvests. The 3D culture system has been found to be capable of supporting long-lived (8 weeks) populations of B and T lymphocytes from peripheral lymphoid organs, in the absence of activation signals, to an extent not achievable by conventional culture techniques. Interestingly, it has been found that 3D-culture B cells display a phenotype that has characteristics of both B1a and B2 cells. These promising preliminary observations suggest that the 3D culture system could be used with success in the study of peripheral-B-lymphocyte biology and in the development of biotechnological techniques and processes.

Wu, J. H. David↗
NASA NTRS1990

Immunology presentation at the 1990 NASA/NSF Antarctica Biomedical Science Working Group

An overview of methodology used for determining human in vitro lymphocyte activation, proliferation and effector cell function was presented and results of previous manned space flight immunology studies from Apollo through Shuttle were reviewed. Until the Shuttle era, lymphocyte assays were not very sensitive and had such large variations among normal subjects that it was difficult to define a consistent effect of space flight. More sensitive assay, however, even with Shuttle missions as brief as 6 days indicate depressed T-cell proliferative responses are routinely observed following space flight. Using a slight modification of the Shuttle assay, five different human stress-immunology models have been studied over the last 6 years in our lab. These have included: academic examinations of medical students having blood drawn during major test periods on three separate groups of first year students and two hypoxia studies (at 25,000 feet in a 6 week chamber ascent to the equivalent of Mount Everest and twice on Pikes Peak at 14,000 feet). These studies are particularly pertinent to Antarctica, since the altitude equivalent of 11,000 feet at the South Pole may affect some of the variables that are being measured in immunology, physiology or cognitive studies. An extravehicular study was performed drawing blood from 35 individuals before and immediately following a chamber exposure study. Preliminary results from 30 Shuttle astronauts investigated immunophenotype analysis and the role of a novel monocyte population in modulating the previously observed suppressed in vitro immune function. The results of the Air Force Academy cadet stress study were also presented.

Meehan, Richard T.↗
NASA NTRS1999

The use of a spaceflight-compatible device to perform WBC surface marker staining and whole-blood mitogenic activation for cytokine detection by flow cytometry

Significant changes have recently been described regarding circulating peripheral immune cells immediately following spaceflight. Existing methods for immunophenotype staining of peripheral blood in terrestrial labs do not meet the constraints for flight on the Space Shuttle. We have recently described the development and use of the Whole Blood Staining Device (WBSD), a simple device for staining flow cytometry specimens during spaceflight. When preparing samples with the WBSD, all liquids are safely contained as the cells are moved through staining, lysis and fixation steps. Here we briefly review the use of the WBSD, and then describe another versatile adaptation, a modification to perform intracellular staining of cytokines for detection by flow cytometry. Alterations in cytokine production have been reported both in ground-based simulated microgravity culture and in astronaut samples returning from spaceflight. Data regarding microgravity effects on cytokine production for specific subpopulations of cells is lacking. Flow cytometric cytokine analysis offers the unique ability to perform simultaneous surface marker analysis and positively identity cytokine producing subsets of cells. The utilization of the WBSD provides the ability to perform rapid and routine mitogenic activation during spaceflight coupled with the ability to perform simultaneous surface marker analysis. The only external requirements for this procedure are an in-flight 37-degree incubator and the capacity for 4-degree storage.

NASA Discipline Regulatory Physiology↗
NASA NTRS2006

Field Immune Assessment during Simulated Planetary Exploration in the Canadian Arctic

Dysregulation of the immune system has been shown to occur during space flight, although the detailed nature of the phenomenon and the clinical risks for exploration class missions has yet to be established. In addition, the growing clinical significance of immune system evaluation combined with epidemic infectious disease rates in third world countries provides a strong rationale for the development of field-compatible clinical immunology techniques and equipment. In July 2002 NASA performed a comprehensive field immunology assessment on crewmembers participating in the Haughton-Mars Project (HMP) on Devon Island in the high Canadian Arctic. The purpose of the study was to evaluate mission-associated effects on the human immune system, as well as to evaluate techniques developed for processing immune samples in remote field locations. Ten HMP-2002 participants volunteered for the study. A field protocol was developed at NASA-JSC for performing sample collection, blood staining/processing for immunophenotype analysis, wholeblood mitogenic culture for functional assessments and cell-sample preservation on-location at Devon Island. Specific assays included peripheral leukocyte distribution; constitutively activated T cells, intracellular cytokine profiles and plasma EBV viral antibody levels. Study timepoints were L-30, midmission and R+60. The protocol developed for immune sample processing in remote field locations functioned properly. Samples were processed in the field location, and stabilized for subsequent analysis at the Johnson Space Center in Houston. The data indicated that some phenotype, immune function and stress hormone changes occurred in the HMP field participants that were largely distinct from pre-mission baseline and post-mission recovery data. These immune changes appear similar to those observed in Astronauts following spaceflight. The sample processing protocol developed for this study may have applications for immune assessment during exploration-class space missions or in remote terrestrial field locations. The data validate the use of the HMP as a ground-based spaceflight/planetary exploration analog for some aspects of human physiology.

Crucian, Brian↗
NASA NTRS2007

Monitoring Immune System Function and Reactivation of Latent Viruses in the Artificial Gravity Pilot Study

Numerous studies have indicated that dysregulation of the immune system occurs during or after spaceflight. Using 21 day -6 deg. head-down tilt bed rest as a spaceflight analog, this study describes the effects of artificial gravity as a daily countermeasure on immunity, stress and reactivation of clinically important latent herpes viruses. The specific aims were to evaluate psychological and physiological stress, to determine the status of the immune system and to quantify reactivation of latent herpes viruses. Blood, saliva, and urine samples were collected from each participating subject at different times throughout the study. An immune assessment was performed on all treatment and control subjects that consisted of a comprehensive peripheral immunophenotype analysis, intracellular cytokine profiles and a measurement of T cell function. The treatment group displayed no differences throughout the course of the study with regards to peripheral leukocyte distribution, cytokine production or T cell function. Shedding of EBV and CMV was quantified by real time PCR in saliva and urine samples, respectively. There was no significant difference in CMV DNA in the treatment group as compared to the control group. EBV and VZV on the other hand showed a mild reactivation during the study. There were no significant differences in plasma cortisol between the control and treatment groups. In addition, no significant differences between antiviral antibody titers (EBV-VCA, -EA, -EBNA, CMV) or tetramer-positive (EBV, CMV) were found between the two groups. EBV DNA copies in blood were typically undetectable but never exceeded 1,500 copies per 10(exp 6) PBMCs. These data indicate that the artificial gravity countermeasure and the 21 day head-down tilt bed rest regimen had no observable adverse effect on immune function.

Mehta, Satish↗
NASA NTRS2007

Monitoring Immune System Function and Reactivation of Latent Viruses in the Artificial Gravity Pilot Study

Numerous studies have indicated that dysregulation of the immune system occurs during or after spaceflight. Using 21 day -6 degrees head-down tilt bed rest as a spaceflight analog, this study describes the effects of artificial gravity (AG) as a daily countermeasure on immunity, stress and reactivation of clinically important latent herpes viruses. The specific aims were to evaluate psychological and physiological stress, to determine the status of the immune system, and to quantify reactivation of latent herpes viruses. Blood, saliva, and urine samples were collected from each participating subject at different times throughout the study. An immune assessment was performed on all treatment and control subjects that consisted of a comprehensive peripheral immunophenotype analysis, intracellular cytokine profiles and a measurement of T cell function. The treatment group displayed no differences throughout the course of the study with regards to peripheral leukocyte distribution, cytokine production or T cell function. Shedding of Epstein barr virus (EBV), Cytomegalovirus (CMV), and Varicella zoster virus (VZV) was quantified by real time PCR in saliva and urine samples, respectively. There was no significant difference in CMV DNA in the treatment group as compared to the control group. EBV and VZV on the other hand showed a mild reactivation during the study. There were no significant differences in cortisol between the control and treatment groups. In addition, no significant differences between antiviral antibody titers (EBV-VCA, -EA, -EBNA, CMV) or tetramer-positive (EBV, CMV) were found between the two groups. EBV DNA copies in blood were typically undetectable but never exceeded 1,500 copies per 106 PBMCs. Overall, these data indicate that the artificial gravity countermeasure and the 21 day head-down tilt bed rest regimen had no observable adverse effect on immune function.

Mehta, Satish K.↗
NASA NTRS2006

Novel Confocal Microscopic and Flow Cytometric Based Assays to Visualize and Detect the (Beta)2-Adrenergic Receptor in Human Lymphocyte and Mononuclear Cell Populations

The data show that immunophenotyping of leukocyte populations with (beta)2AR is possible with the commercially available Ab, although the FC assay is limited to the IST as a result of the Ab binding site to the intracellular C-terminus of the 2AR. The FC assay has applications for measuring alterations in total (beta)2AR in human leukocyte populations as changes in fluorescence. In addition, CM confirms that both surface and intracellular compartments stain positively for the (beta)2AR and can be used for qualitative assays that screen for changes in receptor compartmentalization and localization.

Salicru, A. N.↗
NASA NTRS2009

Validation of Procedures for Monitoring Crewmember Immune Function

There is ample evidence to suggest that space flight leads to immune system dysregulation, however the nature of the phenomenon as it equilibrates over longer flights has not been determined. This dysregulation may be a result of microgravity, confinement, physiological stress, radiation, environment or other mission-associated factors. The clinical risk (if any) for exploration-class space flight is unknown, but may include increased incidence of infection, allergy, hypersensitivity, hematological malignancy or altered wound healing. The objective of this Supplemental Medical Objective (SMO) is to determine the status of the immune system, physiological stress and latent viral reactivation (a clinical outcome that can be measured) during both short and long-duration spaceflight. In addition, this study will develop and validate an immune monitoring strategy consistent with operational flight requirements and constraints. Pre-mission, in-flight and post-flight blood and saliva samples will be obtained from participating crewmembers. Assays included peripheral immunophenotype, T cell function, cytokine profiles (RNA, intracellular, secreted), viral-specific immunity, latent viral reactivation (EBV, CMV, VZV), and stress hormone measurements. This study is currently ongoing. To date, 10 short duration and 5 long-duration crewmembers have completed the study. Technically, the study is progressing well. In-flight blood samples are being collected, and returned for analysis, including functional assays that require live cells. For all in-flight samples to date, sample viability has been acceptable. Preliminary data (n = 4/7; long/short duration, respectively) indicate that distribution of most peripheral leukocyte subsets is largely unaltered during flight. Exceptions include elevated T cells, reduced B/NK cells, increased memory T cells and increased central memory CD8+ T cells. General T cell function, early blastogenesis response to mitogenic stimulation, is markedly reduced in-flight. In-vivo cytokine production profiles are altered, with in-flight dysregulation observed in the Th1/Th2/Treg equilibrium. EBV specific T cell levels are increased during flight, whereas their function is reduced. VZV reactivation was observed inflight and several days post flight with highest levels measured later during long-duration flight. The shedding of CMV in the urine was detected of 4/5 long duration and 4/7 short duration crewmembers. Plasma cortisol was not elevated during flight. Further data will be required to validate the initial observations.

Crucian, Brian↗
NASA NTRS2010

Validation of Procedures for Monitoring Crewmember Immune Function

The objective of this Supplemental Medical Objective (SMO) is to determine the status of the immune system, physiological stress and latent viral reactivation (a clinical outcome that can be measured) during both short and long-duration spaceflight. In addition, this study will develop and validate an immune monitoring strategy consistent with operational flight requirements and constraints. Pre-mission, in-flight and post-flight blood and saliva samples will be obtained from participating crewmembers. Assays included peripheral immunophenotype, T cell function, cytokine profiles, viral-specific immunity, latent viral reactivation (EBV, CMV, VZV), and stress hormone measurements. To date, 18 short duration (now completed) and 8 long-duration crewmembers have completed the study. The long-duration phase of this study is ongoing. For this presentation, the final data set for the short duration subjects will be discussed.

Pierson, Duane↗
NASA NTRS2010

Immune System Dysregulation, Viral Reactivation and Stress During Short-Duration Spaceflight

The objective of this NASA Short-Duration Bioastronautics Investigation (SDBI) was to assess spaceflight-associated immune dysregulation. Many previous studies have investigated this phenomenon post-flight, and found altered distribution and function of the peripheral leukocyte populations. Alterations in cytokine production profiles have also been reported. Unfortunately, post-flight data may be altered by the stress associated with high-G re-entry and readaptation to unit gravity following deconditioning. Therefore, the current study collected blood and saliva samples from crewmembers immediately before landing, and returned those samples to Earth for terrestrial analysis. Assays include peripheral comprehensive immunophenotype, T cell function, cytokine profiles, viral-specific immunity, latent viral reactivation (EBV, CMV, VZV), and stress hormone measurements. A total of 18 short duration crewmembers completed the study and the final data will be presented.

Pierson, Duane↗
NASA NTRS2001

Routine detection of Epstein-Barr virus specific T-cells in the peripheral blood by flow cytometry

The ability to detect cytomegalovirus-specific T-cells (CD4(+)) in the peripheral blood by flow cytometry has been recently described by Picker et al. In this method, cells are incubated with viral antigen and responding (cytokine producing) T-cells are then identified by flow cytometry. To date, this technique has not been reliably used to detect Epstein-Barr virus (EBV)-specific T-cells primarily due to the superantigen/mitogenic properties of the virus which non-specifically activate T-cells. By modifying culture conditions under which the antigens are presented, we have overcome this limitation and developed an assay to detect and quantitate EBV-specific T-cells. The detection of cytokine producing T-cells by flow cytometry requires an extremely strong signal (such as culture in the presence of PMA and ionomycin). Our data indicate that in modified culture conditions (early removal of viral antigen) the non-specific activation of T-cells by EBV is reduced, but antigen presentation will continue uninhibited. Using this method, EBV-specific T-cells may be legitimately detected using flow cytometry. No reduction in the numbers of antigen-specific T-cells was observed by the early removal of target antigen when verified using cytomegalovirus antigen (a virus with no non-specific T-cell activation properties). In EBV-seropositive individuals, the phenotype of the EBV-specific cytokine producing T-cells was evaluated using four-color flow cytometry and found to be CD45(+), CD3(+), CD4(+), CD45RA(-), CD69(+), CD25(-). This phenotype indicates the stimulation of circulating previously unactivated memory T-cells. No cytokine production was observed in CD4(+) T-cells from EBV-seronegative individuals, confirming the specificity of this assay. In addition, the use of four color cytometry (CD45, CD3, CD69, IFNgamma/IL-2) allows the total quantitative assessment of EBV-specific T-cells while monitoring the interference of EBV non-specific mitogenic activity. This method may have significant utility for the monitoring of the immune response to latent virus infection/reactivation.

Non-NASA Center↗
NASA NTRS2000

Acute effects of whole-body proton irradiation on the immune system of the mouse

The acute effects of proton whole-body irradiation on the distribution and function of leukocyte populations in the spleen and blood were examined and compared to the effects of photons derived from a (60)Co gamma-ray source. Adult female C57BL/6 mice were exposed to a single dose (3 Gy at 0.4 Gy/min) of protons at spread-out Bragg peak (SOBP), protons at the distal entry (E) region, or gamma rays and killed humanely at six different times thereafter. Specific differences were noted in the results, thereby suggesting that the kinetics of the response may be variable. However, the lack of significant differences in most assays at most times suggests that the RBE for both entry and peak regions of the Bragg curve was essentially 1.0 under the conditions of this study. The greatest immunodepression was observed at 4 days postexposure. Flow cytometry and mitogenic stimulation analyses of the spleen and peripheral blood demonstrated that lymphocyte populations differ in radiosensitivity, with B (CD19(+)) cells being most sensitive, T (CD3(+)) cells being moderately sensitive, and natural killer (NK1.1(+)) cells being most resistant. B lymphocytes showed the most rapid recovery. Comparison of the T-lymphocyte subsets showed that CD4(+) T helper/inducer cells were more radiosensitive than the CD8(+) T cytotoxic/suppressor cells. These findings should have an impact on future studies designed to maximize protection of normal tissue during and after proton-radiation exposure.

NASA Discipline Radiation Health↗
NASA NTRS1999

Effects of proton and gamma radiation on lymphocyte populations and acute response to antigen

BACKGROUND: The clinical use of proton radiation in the management of cancer, as well as benign disorders, is rapidly increasing. The major goal of this study was to compare the effects of proton and gamma (60Co) radiation on cell-mediated and humoral immunological parameters. MATERIALS AND METHODS: C57BL/6 mice were exposed to a single dose of 3 Gray (Gy) protons or gamma-rays and intraperitoneally injected 1 day later with sheep red blood cells (sRBC). On 4, 10, 15, and 29 days after exposure, subsets from each group were euthanised; nonirradiated controls (with and without sRBC injection) were included. Body and relative spleen weights, leukocyte counts, spontaneous blastogenesis, lymphocyte populations, and anti-sRBC titers were evaluated. RESULTS: The data showed significant depression (p < 0.05) in nearly all assays on days 4 and 10 after irradiation. B lymphocytes (CD19+) were the most radiosensitive, although reconstitution back to normal levels was observed by day 15. T cell (CD3+) and T helper cell (CD4+) recovery was evident by day 29, whereas the T cytotoxic cell (CD8+) count remained significantly below normal. Natural killer cells (NK1.1+) were relatively radioresistant. Anti-sRBC antibody production was slow and low titers were obtained after irradiation. No significant differences were noted between the two types of radiation. CONCLUSIONS: Taken together, the data show that whole-body irradiation with protons or gamma-rays, at the dose employed, results in marked, but transient, immunosuppression. However, at the time points of testing and with the assays used, little or no differences were found between the two forms of radiation.

NASA Discipline Radiation Health↗
NASA NTRS1998

Suppressed PHA activation of T lymphocytes in simulated microgravity is restored by direct activation of protein kinase C

Utilizing clinostatic rotating wall vessel (RWV) bioreactors that simulate aspects of microgravity, we found phytohemagglutinin (PHA) responsiveness to be almost completely diminished. Activation marker expression was significantly reduced in RWV cultures. Furthermore, cytokine secretion profiles suggested that monocytes are not as adversely affected by simulated microgravity as T cells. Reduced cell-cell and cell-substratum interactions may play a role in the loss of PHA responsiveness because placing peripheral blood mononuclear cells (PBMC) within small collagen beads did partially restore PHA responsiveness. However, activation of purified T cells with cross-linked CD2/CD28 and CD3/CD28 antibody pairs was completely suppressed in the RWV, suggesting a defect in signal transduction. Activation of purified T cells with PMA and ionomycin was unaffected by RWV culture. Furthermore, sub-mitogenic doses of PMA alone but not ionomycin alone restored PHA responsiveness of PBMC in RWV culture. Thus our data indicate that during polyclonal activation the signaling pathways upstream of PKC activation are sensitive to simulated microgravity.

NASA Discipline Cell Biology↗
NASA NTRS1996

Effects of spaceflight on rat peripheral blood leukocytes and bone marrow progenitor cells

The white blood cell (WBC) elements and the bone marrow myeloid progenitor cell populations were analyzed to ascertain adaptation to micro-gravity and subsequent readaptation to 1 G in rats flown on the 14-day Spacelab Life Sciences-2 (SLS-2) mission. Bone marrow cells were harvested from one group of rats killed inflight (FD13) and blood was drawn from three other groups at various times. The WBC level was normal on FD14 with the exception of neutrophilia. On FD13, numbers of colony-forming units-granulocyte (CFU-G), CFU-GM, and CFU-M from flight animals were decreased compared with ground controls when incubated with recombinant rat interleukin-3 (rrIL-3) alone or in combination with recombinant human erythropoietin (rhEpo). On recovery (R + 0), flight rats had decreased numbers of total leukocytes and absolute numbers of lymphocytes and monocytes with elevated neutrophils compared with control rats. They had lower numbers of CD4, CD8, CD2, CD3, and B cells in the peripheral blood but no differences in spleen lymphocytes.

NASA Discipline Number 00-00↗
NASA NTRS1995

Immune responses in humans after 60 days of confinement

A confinement experiment in a normobaric diving chamber was undertaken to better understand the effect of confinement and isolation on human psychology and physiology. Pre- and postconfinement blood samples were obtained from four test subjects and control donors to analyze immune responses. No modification in the levels of CD2+, CD3+, CD4+, CD8+, CD19+, and CD56+ cells was observed after confinement. Mitogen-induced T-lymphocyte proliferation and interleukin-2 receptor expression were not altered significantly. Whole blood interferon-alpha and gamma-induction and plasma cortisol levels were also unchanged, as was natural killer cell activity. These data suggest that in humans, no specific components of the immune response are affected by a 2-month isolation and confinement of a small group.

NASA Discipline Number 18-10↗
NASA NTRS1994

Effects of extracellular matrix proteins on macrophage differentiation, growth, and function: comparison of liquid and agar culture systems

Both spaceflight and skeletal unloading suppress the haematopoietic differentiation of macrophages (Sonnenfeld et al., Aviat. Space Environ. Med., 61:648-653, 1990; Armstrong et al., J. Appl. Physiol., 75:2734-2739, 1993). The mechanism behind this reduction in haematopoiesis has yet to be elucidated. However, changes in bone marrow extracellular matrix (ECM) may be involved. To further understand the role of ECM products in macrophage differentiation, we have performed experiments evaluating the effects of fibronectin, laminin, collagen type I, and collagen type IV on macrophage development and function. Bone marrow-derived macrophages cultured on four different ECM substrates in liquid culture medium showed less growth than those cultured on plastic. Significant morphological differences were seen on each of the substrates used. Phenotypically and functionally, as measured by class II major histocompatibility molecule (MHCII) expression, MAC-2 expression, and the secretion of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), these macrophages were similar. In contrast, bone marrow-derived macrophages cultured in suspension, using agar, showed no difference in growth when exposed to ECM proteins. However, IL-6 and TNF-alpha secretion was affected by fibronectin, laminin, collagen type I, and collagen type IV in a concentration-dependent manner. We conclude that the ECM products fibronectin, laminin, collagen type I, and collagen type IV have profound effects on macrophage development and function. Additionally, we suggest that an ECM-supplemented agar culture system provides an environment more analogous to in vivo bone marrow than does a traditional liquid culture system.

Non-NASA Center↗