T cells and antibody-producing B cells carry out immune defense against specific pathogens such as viruses. Antibodies and T cell receptors are highly diverse molecules that can recognize millions of different molecules. Upon encounter of a foreign antigen (such as a molecule from the surface of a virus), T cells and B cells whose receptors match that particular antigen expand dramatically, providing the immune system with a large number of very specific defenders. After an attack is fought off, the overall numbers of specific T and B cells go down again, but a few of them become long-lived so-called "memory cells" that ensure a quick re-mobilization should the same type of attacker strike again.
T cells consist of two major groups: CD4-positive T helper cells (who help other immune cells in mounting an effective response) and CD8-positive killer T cells. HIV infects and destroys CD4-positive cells, leaving patients with a crippled immune system. Throughout the course of HIV disease, however, patients have high levels of HIV-specific killer T cells. Early after initial infection, these cells are able to effectively kill the virus and reduce viral load. On the other hand, during the later stage of disease killer T cells, while still present, seem no longer able to control the virus. In an article in the November 4 issue of the Journal of Clinical Investigation, Premlata Shankar and colleagues from the Center for Blood Research at Harvard Medical School suggest why this might be the case.
The researchers compared killer T cells from HIV infected asymptomic individuals with those from symptomatic AIDS patients. They examined the killer cells ability to eliminate target cells infected with laboratory strains of HIV on one hand, and with autologous virus (isolated from the patient) on the other. What they found is that killer T cells from asymptomatic individuals can recognize and kill both types of target cells. In contrast, the killer T cells from symptomatic patients, while still able to recognize and eliminate the laboratory strain targets, no longer killed target cells that were infected with their own, autologous, virus. This is likely due to the virus propensity to mutate and the in inability of the patients weakened immune system to keep up with the changing virus.
Brooke Grindlinger | EurekAlert!
GLUT5 fluorescent probe fingerprints cancer cells
20.04.2018 | Michigan Technological University
Scientists re-create brain neurons to study obesity and personalize treatment
20.04.2018 | Cedars-Sinai Medical Center
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy