The T cells of the immune system are the main players in the defense against viral infections and tumor cells. On the other hand, they attack the body’s own healthy tissue in autoimmune reactions, which can even be fatal. The body must therefore keep a tight control on T cell activity.

A large number of molecules and messenger are involved in the highly complex regulation of T cell activity. Only recently have researchers discovered that another group of immune cells contibutes to the control of T cell activity. Natural killer cells (NK cells) are part of the innate immunity, i.e. the rapid response force that quickly detects and eliminates infected or malignant cells.

“Studies have shown that NK cells can also kill activated T cells and thus limit their proliferation,” says Michael Platten, Head of Department at the DKFZ and Director of the Neurological University Clinic Mannheim. “However, until now we did not know which feature characterizes T cells as a target for the NK cell.”

When screening activated T cells from healthy donors, Platten’s team identified the protein B7H6 as a recognition molecule for NK cell attacks in a new study. Activated T cells from the blood of patients with autoimmune diseases, cancer or viral infections expose large amounts of B7H6 on their surface. Co-culture experiments in the culture dish showed that NK cells recognize the activated T cells by their B7H6 expression. In contrast, T cells whose B7H6 gene was destroyed with the CRISPR-Cas were protected from the lethal attack of the NK cells.

“The elimination of T cells by NK cells is triggered by an intrinsic mechanism of the T cells. The activated T cells temporarily identify themselves as targets for NK-induced cell lysis,” explains Michael Kilian, first author of the publication, and adds: “This may limit excessive activation and expansion of T cells as a control mechanism to curb destructive immune responses.”

Immune checkpoint inhibitor therapies are neutralized by NK cells

“We now know a number of so-called checkpoint molecules that reduce or enhance the activation of T cells and thus modulate the course of immune reactions. B7H6 can now be classified as a further inhibitory immune checkpoint on T cells,” explains study leader Platten.

Some widespread cancer therapies with drugs from the checkpoint inhibitor (ICI) group are targeting certain inhibitory checkpoint molecules. They activate the immune system against the tumor by releasing the immune brakes. Could the B7H6-mediated elimination of tumor-reactive T cells possibly counteract the effect of ICI cancer immunotherapy? The researchers tested this using tissue samples from patients with esophageal cancer who had received ICI therapy. Those patients who had not responded to ICI had a higher number of NK cells in the tumor tissue and actually had a shorter progression-free survival time.

Cellular immunotherapy more effective in the absence of NK cells

Cellular immunotherapies are becoming increasingly important in cancer medicine. For example, some forms of blood cancer are now often treated with so-called CAR-T cells, which are equipped with customized receptors against the cancer. However, the success of therapy is often limited as the number of therapeutic cells in the patient’s body declines rapidly.

The therapeutic CAR-T cells also carry B7H6 on the cell surface. Could NK cells be responsible for the rapid decline in their numbers after the start of therapy? Experiments with a humanized mouse model suggest this: if NK cells were added during CAR-T cell treatment of leukaemia, the number of therapeutic cells decreased, while the tumour load increased.

“NK control of T cells has the potential to interfere with various forms of cancer immunotherapy. By specifically intervening in this process, it may be possible to modulate T cell immune responses in the future,” explains Michael Platten, head of the current study. With the help of the CRISPR-Cas gene scissors, the researchers now want to protect CAR-T cells from elimination by NK cells in a clinical trial together with the Department of Haematology and Oncology at Heidelberg University Hospital and thus improve the effectiveness of cellular immunotherapy.

Her research and teaching focus on positive psychology, media and new communication technologies, and media and spirituality. The study, published April 13 in Society for Research in Child Development (SRCD), investigates how adolescents perceive and engage with digital communication, including connectedness, positive social comparison, authentic self-presentation, civil participation and self-control.

“This was such an amazing research study to be part of as we all are craving more nuanced answers on how digital technologies affect our children,” said Janicke-Bowles.

Janicke-Bowles’ research contributes to the understanding of digital flourishing (positive social media experiences) among adolescents, highlighting the importance of supportive parental mediation and digital skills in promoting positive digital engagement. Moving forward, interventions aimed at enhancing digital flourishing should consider the role of parental guidance and support in shaping adolescents’ online experiences.

• Adolescents who flourish in their digital communication over time are more likely to have parents who know their way around technology and who actively support their children to positively communicate online.
• For adolescents who digitally flourish less, their self-control over digital communication decreases.
• To increase digital flourishing, interventions can aim in assisting adolescents in their control over their digital communication and encourage parents to take an active role in their young adults’ digital communication.

These findings underscore the significance of parental influence and support in fostering positive digital communication experiences among adolescents.

In addition to her recent research, Janicke-Bowles has a distinguished history of exploring the intersection of media and psychology. As a member of a research team from Florida State and Penn State universities, she received a $1.9 million grant from the John Templeton Foundation to investigate the impact of media content on self-transcendent emotions. Her academic journey, spanning from clinical and media psychology in Germany to mass communication in the United States, underscores her commitment to understanding the profound effects of media on human experiences.

Spintronic devices harness the spin of an electron, rather than its charge, to create current and move information through electronic devices.

“One of the goals in spintronics is to move spin information through a material without also having to move the associated charge, because moving the charge takes more energy — it’s why your phone and computer get hot when you use them for a long time,” says David Waldeck, professor of chemistry in Pitt’s Kenneth P. Dietrich School of Arts and Sciences and co-corresponding author of the work.

Chiral solids are materials that cannot be superimposed on their mirror image — think of your left and right hands, for example. A left-handed glove does not fit on your right hand, and vice-versa. Chirality in spintronic materials allows researchers to control the direction of spin within the material.

“Prior to this work, it was thought that the sense of chirality, or ‘handedness,’ of a material was very important to how and whether the spin would move through that material,” says Dali Sun, associate professor of physics, member of the Organic and Carbon Electronics Lab (ORaCEL) at North Carolina State University and co-corresponding author of the work.

“And when you’re moving the whole electron through the material that is still true. But we found that if you inject pure spin into a chiral material, the absorption of spin current strongly depends on the angle between the spin polarization and chiral axis; in other words, whether the spin polarization is aligned parallel or perpendicular to the chiral axis.”

“We used two different approaches, microwave particle excitation and ultrafast laser heating, to inject pure spin into the selected chiral materials in this study, and both approaches gave us the same conclusion,” says Jun Liu, associate professor of mechanical and aerospace engineering, member of ORaCEL at NC State and co-corresponding author of the work.

“The chiral materials we chose are two chiral cobalt oxide thin films, each with a different chirality, or ‘handedness,'” Liu says. “Non-chiral cobalt oxide thin films are commonly used in modern electronics.”

When the team injected pure spin aligned perpendicular to the material’s chiral axis, they noted that the spin did not travel through the material. However, when the pure spin was aligned either parallel or anti-parallel to the chiral axis, its absorption, or ability to pass through the material, improved by 3000%.

“Since spin can only pass through these chiral materials in one direction, this could enable us to design chiral gateways for use in electronic devices,” Sun says. “And this work also challenges some of what we thought we knew about chiral materials and spin, which is something we want to explore further.”

The work appears in Science Advances and is supported by the Department of Energy under award numbers DE-SC0020992 and ER46430; the Air Force Office of Scientific Research, Multidisciplinary University Research Initiatives (MURI) Program under award numbers FA9550-23-1-0311and FA9550-23-1-0368; and the National Science Foundation under award numbers DMR 2011978 and NSF-ECCS 2246254.

NC State postdoctoral researcher Rui Sun, NC State graduate student Ziqi Wang, and University of Pittsburgh Research Assistant Professor Brian Bloom are co-first authors.

Among those algae most closely related to land plants, diverse body types are found — ranging from single-celled algae to more complex cell filaments. From this group of relatives, an international group of researchers led by the Universities of Göttingen and Nebraska-Lincoln has now generated the first genome data of such complex specimens, on four filamentous “star algae” of the genus Zygnema. Their results were published in Nature Genetics.

The researchers worked with four algal strains in total, two from a culture collection in the USA and two that have been kept safe in the Algal Culture Collection at Göttingen University (SAG). The research involved more than 50 scientists from nine countries who combined a range of cutting-edge sequencing techniques to elucidate the entire DNA sequence of these algae. The advanced methods enabled them to generate complete genomes for these organisms at the level of whole chromosomes — something that had never been done before on this group of algae. Comparing the genes on the genomes with those of other plants and algae led to the discovery of specific overabundances of signalling genes and environmental response factors. Dr Iker Irisarri, Leibniz Institute for the Analysis of Biodiversity Change, explains: “Many of these genes underpin molecular functions that were important for the emergence of the first multicellular terrestrial plants. It is fascinating that the genetic building blocks, whose origins predate land plants by millions of years, duplicated and diversified in the ancestors of plants and algae and, in doing so, enabled the evolution of more specialized molecular machinery.”

Professor Jan de Vries, University of Göttingen, says: “Not only do we present a valuable, high-quality resource for the entire plant scientific community, who can now explore these genome data, our analyses uncovered intricate connections between environmental responses. This sheds light on one of land plants’ most important features: their ability to adjust their growth and development so that it aligns with the environment in which they dwell — a process known as developmental plasticity.”