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Comment by Dr. Krishna Kumari Challa on July 31, 2025 at 9:07am

Anticipation of a virtual infectious pathogen is enough to prompt real biological defenses

Researchers  report that neural anticipation of virtual infection triggers an immune response through activation of innate lymphoid cells.

Innate lymphoid cells (ILCs) are a type of immune cell crucial for early immune responses. They do not rely on antigen recognition like adaptive immune cells but respond quickly and effectively to various inflammatory signals and pathogen-associated cues, playing an essential role in early defense.

Protecting the body from pathogens typically involves a multitude of responses after actual contact. An anticipatory biological immune reaction to an infection had not been previously demonstrated.

In the study, "Neural anticipation of virtual infection triggers an immune response," published in Nature Neuroscience, researchers designed a multisensory experiment to test whether human brains could anticipate potential infections through virtual reality (VR) and initiate early immune system reactions.

Participants in the experiments conducted exposed to infectious avatars showed an expansion of peripersonal space (PPS) effects, measurable as faster reaction times to tactile stimulation even at farther avatar distances. EEG analyses, performed on a separate group of 32 participants, revealed anticipatory neural responses in multisensory-motor areas and activation within the salience network, particularly the anterior insula and medial prefrontal cortex.

ILCs were significantly modulated in frequency and activation by virtual infections, resembling immune reactions to real pathogens, assessed through comparison with an influenza vaccine cohort. Specifically, both virtual and real infections induced decreases in ILC1s and increases in ILC2s and ILC precursors, indicative of active immune mobilization.

Researchers concluded that the human immune system activates not only after physical contact but also when infection threats breach the functional boundary of body-environment interaction, represented by PPS. This anticipatory neuro-immune mechanism would have advantages, enabling rapid responses to potential infections, even in virtual contexts.

Sara Trabanelli et al, Neural anticipation of virtual infection triggers an immune response, Nature Neuroscience (2025). DOI: 10.1038/s41593-025-02008-y

Comment by Dr. Krishna Kumari Challa on July 31, 2025 at 9:01am

'One and done': A single shot at birth may shield children from HIV for years

A new study in Nature shows that delivering a single injection of gene therapy at birth may offer years-long protection against HIV, tapping into a critical window in early life that could reshape the fight against pediatric infections in high-risk regions.

This study is among the first to show that the first weeks of life, when the immune system is naturally more tolerant, may be the optimal window for delivering gene therapies that would otherwise be rejected at older ages.

In the study, nonhuman primates received a gene therapy that programs cells to continuously produce HIV-fighting antibodies. Timing proved critical to the one-time treatment offering long-term protection.

Those that received the treatment within their first month of life were protected from infection for at least three years with no need for a booster, potentially signifying coverage into adolescence in humans. In contrast, those treated at 8–12 weeks showed a more developed, less tolerant immune system that did not accept the treatment as effectively.

As long as the treatment is delivered close to birth, the baby's immune system will accept it and believe it's part of itself.

Mauricio Martins, Determinants of successful AAV delivery of HIV-1 bNAbs in early life, Nature (2025). DOI: 10.1038/s41586-025-09330-2. www.nature.com/articles/s41586-025-09330-2

Comment by Dr. Krishna Kumari Challa on July 30, 2025 at 12:44pm

The brain clocks sickness from a mile off

The brain fires up immune cells when sick people are nearby

At the mere sight of a sick person, the brain kickstarts an immune response mimicking the body’s response to an actual infection. In a study, volunteers donned virtual reality headsets to view human avatars with rashes, coughs or other symptoms of illness. Researchers found that the sight of a sick person activates the brain’s ‘salience network’: a collection of regions involved in recognizing and responding to threats. This activity triggered a surge in innate lymphoid cells, which are part of the body’s first line of defence against invaders.

https://www.nature.com/articles/s41593-025-02008-y?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on July 30, 2025 at 12:04pm

Aging dampens lupus by reducing overactive immune genes in older adults

 Researchers have found that certain antiviral genes become less active over time in lupus, revealing why some patients see their symptoms fade as they age.

Lupus, an autoimmune disease, causes the immune system's first-line viral defenses—known as interferons—to attack the body. Nearly every organ is at risk, leading to conditions like kidney and heart disease.

But unlike many other autoimmune or chronic illnesses, lupus can improve as patients reach their 60s and 70s.

By analyzing blood samples from patients across the age spectrum, scientists discovered that aging turns down the activity of certain immune genes in people with lupus, leading to fewer interferons and other inflammatory proteins in the body.

The study found that in healthy adults, inflammation-related genes and proteins rose slowly over the years, a process that has been dubbed "inflammaging." In patients with lupus, however, the expression of these genes and proteins was abnormally high in midlife but decreased as the decades went by.

"Inflammaging seemed to be reversed in the lupus patients", say the researchers.

"But it wasn't fully reversed. The lupus patients still had a greater level of inflammatory signaling compared to healthy adults in older age."

Rithwik Narendra et al, Epigenetic attenuation of interferon signaling is associated with aging-related improvements in systemic lupus erythematosus, Science Translational Medicine (2025). DOI: 10.1126/scitranslmed.adt5550

Comment by Dr. Krishna Kumari Challa on July 30, 2025 at 11:57am

Australopithecus afarensis, which lived between 3.9 and 2.9 million years ago, is widely regarded as either a direct ancestor of modern humans or a species very closely related to a direct ancestor.

Yet, its high degree of sexual dimorphism suggests that early hominins may have lived in social systems that were far more hierarchical and competitive than once thought.

Meanwhile, the less dimorphic A. africanus—which overlapped in time with A. afarensis but first shows up and last appears in the fossil record slightly later, between roughly 3.3 and 2.1 million years ago—may represent a different evolutionary branch on the hominin tree, or perhaps a transitional stage in the development of more human-like social behavior.
We typically place these early hominins together in a single group called the gracile australopiths, a group of species that are thought to have interacted with their physical and social environments in very similar ways.
while that's true to a certain extent—the evidence suggests that both these species may have had social organizations more like gorillas than modern people—the significant difference in the amount of dimorphism in these two extinct species suggests that these closely related hominin species were subject to selection pressures more distinct than the selection pressures applied to any pair of similarly closely related living ape species, highlighting the diversity of ways that our extinct ancestors and close relatives interacted with the world.

 Adam D. Gordon, Sexual Size Dimorphism in Australopithecus: Postcranial Dimorphism Differs Significantly Among Australopithecusafarensis, A. africanus, and Modern Humans Despite Low‐Power Resampling Analyses, American Journal of Biological Anthropology (2025). DOI: 10.1002/ajpa.70093

Part 3

Comment by Dr. Krishna Kumari Challa on July 30, 2025 at 11:55am

Sexual size dimorphism (SSD) isn't just a physical trait—it reveals something deeper about behavior and evolutionary strategy. Consistent with sexual selection theory, high SSD in living primates typically correlates with strong male–male competition and social structures allowing for polygynous mating systems, where one or a few large males monopolize reproductive access to multiple females.

In contrast, low SSD can be found in any species, but tends to be found in those with pair-bonded social structures and low competition for mating opportunities. Modern human populations exhibit low to moderate SSD, where males tend to be slightly larger than females on average but with substantial overlap in size between the sexes.

High SSD in living primates can also be associated with intense resource stress—when food is scarce, small healthy females can get enough food to meet their own metabolic needs and store energy for reproduction faster than larger females can, leading to more offspring with smaller mothers in the next generation and a resulting greater difference in male and female size.

The high SSD identified in both Australopithecus species suggests a high degree of competition among males, similar to that of chimpanzees or even gorillas, while the difference between the two fossil species may be due to a difference in the intensity of those forces of sexual selection and/or a difference in the intensity of resource stress in their environments (e.g., a difference in the length of dry seasons with low fruit availability) and its impact on female body size.

In any event, the high SSD in these fossil hominins contrasts sharply with the more balanced size seen in modern humans and offers a glimpse into a different model of early hominin life—one where large size may have been a key factor in male reproductive success for competitive reasons, and small size may have been a key factor for females for energetic reasons.

Part 2

Comment by Dr. Krishna Kumari Challa on July 30, 2025 at 11:41am

Early human ancestors showed extreme size differences between males and females

A newly published study has found that males of some of our earliest known ancestors were significantly larger than females. The pronounced difference in body size present in both Australopithecus afarensis (the East African species that includes the famous fossil "Lucy") and A. africanus (a closely related southern African species) suggests the ancient hominins may have lived in social systems marked by intense competition among males, leading to the substantial size disparity among the sexes.

The research  appears in the July issue of the American Journal of Biological Anthropology. Using a novel approach that overcomes the limitations of incomplete fossil records, the study reveals that both A. afarensis and A. africanus were more sexually dimorphic than modern humans—and in some cases, even more than gorillas.

These weren't modest differences. In the case of A. afarensis, males were dramatically larger than females—possibly more so than in any living great ape. And although both of these extinct hominin species exhibited greater sex-specific size differences than modern humans do, they were also more different from each other in this respect than living ape species are, suggesting a greater diversity of evolutionary pressures acting on these closely related species than we had previously appreciated.

The results add new depth to interpretations of the fossil record. Earlier studies had reached differing conclusions about dimorphism in A. afarensis, with some suggesting it resembled the relatively low levels seen in modern humans. Furthermore, direct comparison between fossil species had not previously been made because investigations were limited by incomplete fossil samples and insufficient statistical power to detect real differences.

This analysis overcomes these issues by using an iterative resampling method that mimics the missing data structure in both fossil species when sampling from skeletal material of living species, allowing the inclusion of multiple fossil individuals even when those individual specimens are fragmentary.

This study provides strong evidence that sex-specific evolutionary pressures—likely involving both male competition for mates and resource stress acting more intensely on female size due to the metabolic constraints of pregnancy and lactation—played a larger role in early hominin evolution than previously thought. 

Part 1

Comment by Dr. Krishna Kumari Challa on July 30, 2025 at 9:42am

About 82% of deaths averted occurred among individuals vaccinated before any infection and 57% during the omicron period. Persons aged 60 years or older accounted for 89.6% of lives saved, with children and adolescents contributing just 0.01%. Sensitivity analyses yielded a range of 1.4–4.0 million deaths and 7.4–23.6 million life-years saved.

Life-year benefits tracked a similar age gradient with individuals over 60 making up 76% of the total years saved, with negligible contributions (<0.5 %) from those under 30. Long‑term‑care residents, who accounted for 11.8 % of deaths averted, only added 2% to life‑years saved. Authors conclude that vaccination offered a clear mortality benefit during 2020–2024, largely among older adults, and describe their estimates as conservative.

John P. A. Ioannidis et al, Global Estimates of Lives and Life-Years Saved by COVID-19 Vaccination During 2020-2024, JAMA Health Forum (2025). DOI: 10.1001/jamahealthforum.2025.2223

Part 2

Comment by Dr. Krishna Kumari Challa on July 30, 2025 at 9:41am

Global analysis finds 14.8 million life-years added by COVID-19 vaccinations

A Stanford University-led investigation into the COVID-19 vaccination effort reports that it averted an estimated 2.533 million deaths and 14.8 million life-years worldwide between 2020 and 2024.

Amidst much controversy in the public sphere, a worldwide vaccination campaign took place to counter the novel and deadly COVID-19 virus as it spread to every corner of the globe. As the pandemic spread, so did misinformation, disinformation, and real-time updates on risk and prevention that occasionally changed as events unfolded.

Around 7 million people died as a direct result of the virus. Estimating the human toll prevented by vaccines remains a crucial question, both for  public education and for future public health planning.

In the study, "Global Estimates of Lives and Life-Years Saved by COVID-19 Vaccination During 2020-2024," published in JAMA Health Forum, researchers conducted a comparative-effectiveness analysis to quantify life-saving effects attributable to vaccination from December 2020 through October 1, 2024.

Nearly 8 billion individuals (the 2021 world population) served as the study cohort, partitioned by seven age tiers: community versus long-term-care residence, and pre-omicron versus omicron periods.

Investigators estimated deaths averted by multiplying stratum-specific population, projected infection proportion, infection fatality rate, and vaccine effectiveness; life-year gains combined those results with life expectancy and a health-status adjustment factor.

Findings show 2.533 million lives saved, equating to one death averted per 5,400 vaccine doses. Life-year gains reached 14.8 million, or one life-year per 900 doses.

Part 1

Comment by Dr. Krishna Kumari Challa on July 30, 2025 at 9:37am

Rigid and negative thought patterns linked to increasing political polarization online

The ideological divide between opposing political groups has been drastically increasing in various countries worldwide. This phenomenon, known as political polarization, can lead to greater social division, extremism and political violence.

Researchers  recently carried out a study aimed at better understanding the psychology of political polarization and, more specifically, the thought patterns associated with extreme and opposing political views. Their findings, published in Communications Psychology, unveiled a link between the rising political polarization online and distorted ways of thinking often associated with some mental health disorders, including anxiety and depression.

Distorted thinking appeared to precede polarization in some cases. This suggests that how we think—emotionally and cognitively—may be a key driver of polarization, not just what we believe. Of course, their observations do not imply causality.

Andy Edinger et al, Cognitive distortions are associated with increasing political polarization, Communications Psychology (2025). DOI: 10.1038/s44271-025-00289-4

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