But precisely how this natural protein works its magic on the cells of the immune system is not well understood. Now, however, in research that may have implications for developing vaccines against HIV and cancer, a team of scientists from the University of Wisconsin-Madison has found that the timing of interleuin-7 therapy is critical for increasing the number of killer cells that zero in on and destroy virus-infected cells.
Writing in the current online issue (Feb. 1, 2008) of the Journal of Clinical Investigation, a team led by UW-Madison School of Veterinary Medicine Professor of pathobiological sciences Marulasiddappa Suresh reports that therapeutic administration of interleukin-7 can be linked to a stage of early infection to effectively increase the number of a type of killer cell that recognizes and selectively assassinates virus-infected cells.
"These cells need to get interleukin-7 for their survival," explains Suresh, of the killer immune cell known as CD8 T cells, a type of white blood cell that attacks virus-infected cells, foreign cells and cancer cells. Interleukin-7 is produced in very small amounts in bone marrow, spleen, and the thymus, but scientists have been able to isolate and synthesize the agent, which is now in pre-clinical testing for a variety of conditions.
"This is one of the most exciting cytokines in pre-clinical human trials," says Suresh. "The idea is that it might be used as an immune restorative agent. It is absolutely essential for normal development and functioning of the immune system."
Effectively stimulating the immune system -- the complex of organs and cells that defends the body against infection and disease -- is a grail of biomedical science in the fight against infectious diseases.
Suresh explains that upon infection, the body unleashes an army of T cells to fight infected or rogue cells. But when the body perceives an infection may be contained, the number of T cells it deploys is dramatically reduced. However, a certain number of T cells, known as memory cells and that are capable of recognizing a recently vanquished foe, remain. Stimulating memory T and B cells is the basis of vaccination, but vaccines often do not induce a sufficient number of memory CD8 T cells.
Interleukin-7 is a well-studied growth factor that is known to help generate and maintain the immune system's “memory” CD8 T cells, which have the ability to remember the identity of its targets, such as cancer cells or cells that have been taken over by a virus. A paucity of interleukin-7 is believed to limit the survival and persistence of memoryCD8 T cells.
Despite the promise of interleukin-7 as a means to bolster immunity, an optimal treatment regimen has yet to be determined.
In studies in mice, Suresh and his colleagues found that T cell memory is best enhanced when interleukin-7 is administered during a phase of infection when the number of T cells is ramping down.
In the new Wisconsin study, Suresh's group gave interleukin-7 to mice during different stages of a viral infection. They found that by administering interleukin-7 when the number of T cells is in decline, it is possible to increase the number of memory CD8 T cells that remain to stand guard and protect against re-infection.
"The purpose of the immune response is to expand these cells," says Suresh, explaining that T cells act like serial killers, snuffing one infected cell after another until the viral infection is controlled.
During the expansion phase of infection, when the body is generating the most T cells, administration of interleukin-7 seems to have no effect, according to Suresh. But during the contraction phase, memory is increased.
"We tried this in a DNA vaccine and it works," says Suresh. "Even with the weakest vaccine, we could increase the memory cells and improve protection against infection. What this shows is that the number of memory cells are not predetermined. You can increase them and interleukin-7 drives their proliferation."
Marulasiddappa Suresh | EurekAlert!
Cell Division at High Speed
19.06.2019 | Julius-Maximilians-Universität Würzburg
Monitoring biodiversity with sound: how machines can enrich our knowledge
18.06.2019 | Georg-August-Universität Göttingen
The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.
Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...
The well-known representation of chemical elements is just one example of how objects can be arranged and classified
The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...
Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.
Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...
Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.
The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...
Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.
The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
19.06.2019 | Physics and Astronomy
19.06.2019 | Information Technology
19.06.2019 | Materials Sciences