ALBERT

Description: In vitro three-dimensional (3D) human broncho-epithelial (HBE) tissue-like assemblies (3D HBE TLAs) from this point forward referred to as TLAs were engineered in Rotating Wall Vessel (RWV) technology to mimic the characteristics of in vivo tissues thus providing a tool to study human respiratory viruses and host cell interactions. The TLAs were bioengineered onto collagen-coated cyclodextran microcarriers using primary human mesenchymal bronchial-tracheal cells (HBTC) as the foundation matrix and an adult human bronchial epithelial immortalized cell line (BEAS-2B) as the overlying component. The resulting TLAs share significant characteristics with in vivo human respiratory epithelium including polarization, tight junctions, desmosomes, and microvilli. The presence of tissue-like differentiation markers including villin, keratins, and specific lung epithelium markers, as well as the production of tissue mucin, further confirm these TLAs differentiated into tissues functionally similar to in vivo tissues. Increasing virus titers for human respiratory syncytial virus (wtRSVA2) and parainfluenza virus type 3 (wtPIV3 JS) and the detection of membrane bound glycoproteins over time confirm productive infections with both viruses. Therefore, TLAs mimic aspects of the human respiratory epithelium and provide a unique capability to study the interactions of respiratory viruses and their primary target tissue independent of the host's immune system.

Description: A three-dimensional (3-D) tissue-like assembly (TLA) of human bronchial-tracheal mesenchymal (HBTC) cells with an overlay of human bronchial epithelial (BEAS-2B) cells was constructed using a NASA Bioreactor to survey the infectivity of SARS-CoV. This TLA was inoculated with a low passage number Urbani strain of SARS-CoV. At selected intervals over a 10-day period, media and cell aliquots of the 3-D TLA were harvested for viral titer assay and for light and electron microscopy examination. All viral titer assays were negative in both BEAS-2B two-dimensional monolayer and TLA. Light microscopy immunohistochemistry demonstrated antigen-antibody reactivity with anti-SARS-CoV polyclonal antibody to spike and nuclear proteins on cell membranes and cytoplasm. Coronavirus Group 2 cross-reactivity was demonstrated by positive reaction to anti-FIPV 1 and anti-FIPV 1 and 2 antibodies. TLA examination by transmission electron microscopy indicated increasing cytoplasmic vacuolation with numerous electron-dense bodies measuring 45 to 270 nm from days 4 through 10. There was no evidence of membrane blebbing, membrane duplication, or fragmentation of organelles in the TLAs. However, progressive disruption of endoplasmic reticulum was observed throughout the cells. Antibody response to SARS-CoV specific spike and nucleocapsid glycoproteins, cross-reactivity with FIPV antibodies, and the cytoplasmic pathology suggests this HBTE TLA model is permissive to SARS-CoV infection.

Description: The old adage we are our own worst enemies may perhaps be the most profound statement ever made when applied to man s desire for extraterrestrial exploration and habitation of Space. Consider the immune system protects the integrity of the entire human physiology and is comprised of two basic elements the adaptive or circulating and the innate immune system. Failure of the components of the adaptive system leads to venerability of the innate system from opportunistic microbes; viral, bacteria, and fungal, which surround us, are transported on our skin, and commonly inhabit the human physiology as normal and imunosuppressed parasites. The fine balance which is maintained for the preponderance of our normal lives, save immune disorders and disease, is deregulated in microgravity. Thus analogue systems to study these potential Risks are essential for our progress in conquering Space exploration and habitation. In this study we employed two known physiological target tissues in which the reactivation of hCMV and VZV occurs, human neural and lung systems created for the study and interaction of these herpes viruses independently and simultaneously on the innate immune system. Normal human neural and lung tissue analogues called tissue like assemblies (TLAs) were infected with low MOIs of approximately 2 x 10(exp -5) pfu hCMV or VZV and established active but prolonged low grade infections which spanned .7-1.5 months in length. These infections were characterized by the ability to continuously produce each of the viruses without expiration of the host cultures. Verification and quantification of viral replication was confirmed via RT_PCR, IHC, and confocal spectral analyses of the respective essential viral genomes. All host TLAs maintained the ability to actively proliferate throughout the entire duration of the experiments as is analogous to normal in vivo physiological conditions. These data represent a significant advance in the ability to study the triggering mechanisms which surround Herpes vial reactivation and proliferation. Additionally, prolonged replication of these viruses will allow the tracking of viral genomic shift.