Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Visualizing the Kiss of Death

06.12.2004


At the 2004 ASCB Meeting: Visualizing the Kiss of Death



The very idea threw the Victorian poet Alfred Lord Tennyson into a funk. “Nature, red in tooth and claw,” Tennyson called the nightmarish idea that life was an unending battle to eat or be eaten. If only Tennyson could have seen the latest self-defense videos made by Daniela Malide and others at the National Institutes of Health in Bethesda, MD. Using time-lapse confocal laser scanning microscopy, Malide captured human T-cells picking up distress signals from cells infected with a virus and zeroing in for the kill.

Scientists have worked out experimentally many of the mechanisms and tactics of the immuno-surveillance system but Malide’s real-time videos show the action as it unfolds. The videos also revealed for the first time that “killer” T-cells take far longer to dispatch their viral enemies than was generally believed. Instead of a brisk 10-minute rubout, these killer T-cells can take up to two hours to mount a fatal assault.


The struggle begins when MHC (Major Histocompatibility Complex) Class I molecules inside cells infected with vaccinia virus, the virus used for small pox vaccination, grab bits of scrap viral protein and present them on the cell surface to flag down passing Tcd8+ killer cells. Nearly all cell types in the body have MHC class I molecules and the small pieces of viral proteins or peptides that they collect in the cytosol are a byproduct of imperfect protein synthesis by the virus. To passing T-cells, these viral peptides are highly suspect and call for a closer look. The T-cells arrive “ready to kill,” packing death-inducing proteins (perforin and granzymes) in their lytic granules.

On the video, the T-cells make contact, fluorescent labels marking their cell surface and interior poison granules. Inside the infected cells, another fluorescent label shows the vaccinia virus glowing brightly as it goes about its own deadly business of replicating. Then comes the surprise. Says Malide, “We found that contrary to the general notion that target cell lysis often occurs within 10 minutes of establishing firm contact with T-cells, lysis occurs with much greater delay, generally 45 to 120 minutes. During this time, many T-cells remain in contact with target cells, and we frequently see the transfer of viral proteins and MHC Class I molecules to T-cells.”

Only after this prolonged interaction does the killer cell kill. The perforin and granzyme explode inside the infected cell, the glowing vaccinia virus goes abruptly dark, and the target cell disintegrates. Even viewed through a microscope, it is a violent ending, revealing Nature to be, if not red in tooth and claw, then fluorescent green in killer T-cells.

Real Time Visualization of Cytotoxic T Lymphocyte Killing of Vaccinia Virus Infected Target Cells, D. Malide,1 S. Basta,2 J. R. Bennink,2 J. W. Yewdell2 ; 1 Light Microscopy Facility, NIH-NHLBI, Bethesda, MD, 2 Laboratory of Viral Diseases, NIH-NIAID, Bethesda, MD.

At the ASCB Meeting: Session 173, Minisymposium 4: Cell Biology of the Immune System, Room 146. Author presents: Sunday, Dec. 5, 3:30 — 5:45 PM.

| newswise
Further information:
http://www.ascb.org/publicpolicy/pressbooks/pressbook04.html
http://www.ascb.org

More articles from Life Sciences:

nachricht Historical rainfall levels are significant in carbon emissions from soil
30.05.2017 | University of Texas at Austin

nachricht 3D printer inks from the woods
30.05.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New Method of Characterizing Graphene

Scientists have developed a new method of characterizing graphene’s properties without applying disruptive electrical contacts, allowing them to investigate both the resistance and quantum capacitance of graphene and other two-dimensional materials. Researchers from the Swiss Nanoscience Institute and the University of Basel’s Department of Physics reported their findings in the journal Physical Review Applied.

Graphene consists of a single layer of carbon atoms. It is transparent, harder than diamond and stronger than steel, yet flexible, and a significantly better...

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

3D printer inks from the woods

30.05.2017 | Life Sciences

How circadian clocks communicate with each other

30.05.2017 | Life Sciences

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible

30.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>