The findings, published Sept. 20 in the journal Science Immunology, offer a mechanistic understanding for how cells respond to heat and could explain how chronic inflammation contributes to the development of cancer.

The impact of fever temperatures on cells is a relatively understudied area, said Jeff Rathmell, PhD, Cornelius Vanderbilt Professor of Immunobiology and corresponding author of the new study. Most of the existing temperature-related research relates to agriculture and how extreme temperatures impact crops and livestock, he noted. It’s challenging to change the temperature of animal models without causing stress, and cells in the laboratory are generally cultured in incubators that are set at human body temperature: 37 degrees Celsius (98.6 degrees Fahrenheit).

“Standard body temperature is not actually the temperature for most inflammatory processes, but few have really gone to the trouble to see what happens when you change the temperature,” said Rathmell, who also directs the Vanderbilt Center for Immunobiology.

Graduate student Darren Heintzman was interested in the impact of fevers for personal reasons: Before he joined the Rathmell lab, his father developed an autoimmune disease and had a constant fever for months on end.

“I started thinking about what an increased set point temperature like that might do. It was intriguing,” Heintzman said.

Heintzman cultured immune system T cells at 39 degrees Celsius (about 102 degrees Fahrenheit). He found that heat increased helper T cell metabolism, proliferation and inflammatory effector activity and decreased regulatory T cell suppressive capacity.

“If you think about a normal response to infection, it makes a lot of sense: You want effector (helper) T cells to be better at responding to the pathogen, and you want suppressor (regulatory) T cells to not suppress the immune response,” Heintzman said.

But the researchers also made an unexpected discovery — that a certain subset of helper T cells, called Th1 cells, developed mitochondrial stress and DNA damage, and some of them died. The finding was confusing, the researchers said, because Th1 cells are involved in settings where there is often fever, like viral infections. Why would the cells that are needed to fight the infection die?

The researchers discovered that only a portion of the Th1 cells die, and that the rest undergo an adaptation, change their mitochondria, and become more resistant to stress.

“There’s a wave of stress, and some of the cells die, but the ones that adapt and survive are better — they proliferate more and make more cytokine (immune signaling molecules),” Rathmell said.

Heintzman was able to define the molecular events of the cell response to fever temperatures. He found that heat rapidly impaired electron transport chain complex 1 (ETC1), a mitochondrial protein complex that generates energy. ETC1 impairment set off signaling mechanisms that led to DNA damage and activation of the tumor suppressor protein p53, which aids DNA repair or triggers cell death to maintain genome integrity. Th1 cells were more sensitive to impaired ETC1 than other T cell subtypes.

The researchers found Th1 cells with similar changes in sequencing databases for samples from patients with Crohn’s disease and rheumatoid arthritis, adding support to the molecular signaling pathway they defined.

“We think this response is a fundamental way that cells can sense heat and respond to stress,” Rathmell said. “Temperature varies across tissues and changes all the time, and we don’t really know what it does. If temperature changes shift the way cells are forced to do metabolism because of ETC1, that’s going to have a big impact. This is fundamental textbook kind of stuff.”

The findings suggest that heat can be mutagenic — when cells that respond with mitochondrial stress don’t properly repair the DNA damage or die.

“Chronic inflammation with sustained periods of elevated tissue temperatures could explain how some cells become tumorigenic,” Heintzman said, noting that up to 25% of cancers are linked to chronic inflammation.

“People ask me, ‘Is fever good or bad?'” Rathmell added. “The short answer is: A little bit of fever is good, but a lot of fever is bad. We already knew that, but now we have a mechanism for why it’s bad.”

The research was supported by the National Institutes of Health (grants R01DK105550, R01HL136664, R01CA217987, R01HL118979, R01AI153167, R01CA245134, T32AI112541, T32DK101003, T32AR059039, K00CA253718), Lupus Research Alliance, Waddell Walker Hancock Cancer Discovery Fund, and National Science Foundation.

Several years ago, MIT researchers showed that administering a series of escalating doses of an HIV vaccine over a two-week period could help overcome a part of that challenge by generating larger quantities of neutralizing antibodies. However, a multidose vaccine regimen administered over a short time is not practical for mass vaccination campaigns.

In a new study, the researchers have now found that they can achieve a similar immune response with just two doses, given one week apart. The first dose, which is much smaller, prepares the immune system to respond more powerfully to the second, larger dose.

This study, which was performed by bringing together computational modeling and experiments in mice, used an HIV envelope protein as the vaccine. A single-dose version of this vaccine is now in clinical trials, and the researchers hope to establish another study group that will receive the vaccine on a two-dose schedule.

“By bringing together the physical and life sciences, we shed light on some basic immunological questions that helped develop this two-dose schedule to mimic the multiple-dose regimen,” says Arup Chakraborty, the John M. Deutch Institute Professor at MIT and a member of MIT’s Institute for Medical Engineering and Science and the Ragon Institute of MIT, MGH and Harvard University.

This approach may also generalize to vaccines for other diseases, Chakraborty notes.

Chakraborty and Darrell Irvine, a former MIT professor of biological engineering and materials science and engineering and member of the Koch Institute for Integrative Cancer Research, who is now a professor of immunology and microbiology at the Scripps Research Institute, are the senior authors of the study, which appears in Science Immunology. The lead authors of the paper are Sachin Bhagchandani PhD ’23 and Leerang Yang PhD ’24.

Neutralizing antibodies

Each year, HIV infects more than 1 million people around the world, and some of those people do not have access to antiviral drugs. An effective vaccine could prevent many of those infections. One promising vaccine now in clinical trials consists of an HIV protein called an envelope trimer, along with a nanoparticle called SMNP. The nanoparticle, developed by Irvine’s lab, acts as an adjuvant that helps recruit a stronger B cell response to the vaccine.

In clinical trials, this vaccine and other experimental vaccines have been given as just one dose. However, there is growing evidence that a series of doses is more effective at generating broadly neutralizing antibodies. The seven-dose regimen, the researchers believe, works well because it mimics what happens when the body is exposed to a virus: The immune system builds up a strong response as more viral proteins, or antigens, accumulate in the body.

In the new study, the MIT team investigated how this response develops and explored whether they could achieve the same effect using a smaller number of vaccine doses.

“Giving seven doses just isn’t feasible for mass vaccination,” Bhagchandani says. “We wanted to identify some of the critical elements necessary for the success of this escalating dose, and to explore whether that knowledge could allow us to reduce the number of doses.”

The researchers began by comparing the effects of one, two, three, four, five, six, or seven doses, all given over a 12-day period. They initially found that while three or more doses generated strong antibody responses, two doses did not. However, by tweaking the dose intervals and ratios, the researchers discovered that giving 20 percent of the vaccine in the first dose and 80 percent in a second dose, seven days later, achieved just as good a response as the seven-dose schedule.

“It was clear that understanding the mechanisms behind this phenomenon would be crucial for future clinical translation,” Yang says. “Even if the ideal dosing ratio and timing may differ for humans, the underlying mechanistic principles will likely remain the same.”

Using a computational model, the researchers explored what was happening in each of these dosing scenarios. This work showed that when all of the vaccine is given as one dose, most of the antigen gets chopped into fragments before it reaches the lymph nodes. Lymph nodes are where B cells become activated to target a particular antigen, within structures known as germinal centers.

When only a tiny amount of the intact antigen reaches these germinal centers, B cells can’t come up with a strong response against that antigen.

However, a very small number of B cells do arise that produce antibodies targeting the intact antigen. So, giving a small amount in the first dose does not “waste” much antigen but allows some B cells and antibodies to develop. If a second, larger dose is given a week later, those antibodies bind to the antigen before it can be broken down and escort it into the lymph node. This allows more B cells to be exposed to that antigen and eventually leads to a large population of B cells that can target it.

“The early doses generate some small amounts of antibody, and that’s enough to then bind to the vaccine of the later doses, protect it, and target it to the lymph node. That’s how we realized that we don’t need to give seven doses,” Bhagchandani says. “A small initial dose will generate this antibody and then when you give the larger dose, it can again be protected because that antibody will bind to it and traffic it to the lymph node.”

T-cell boost

Those antigens may stay in the germinal centers for weeks or even longer, allowing more B cells to come in and be exposed to them, making it more likely that diverse types of antibodies will develop.

The researchers also found that the two-dose schedule induces a stronger T-cell response. The first dose activates dendritic cells, which promote inflammation and T-cell activation. Then, when the second dose arrives, even more dendritic cells are stimulated, further boosting the T-cell response.

Overall, the two-dose regimen resulted in a fivefold improvement in the T-cell response and a 60-fold improvement in the antibody response, compared to a single vaccine dose.

“Reducing the ‘escalating dose’ strategy down to two shots makes it much more practical for clinical implementation. Further, a number of technologies are in development that could mimic the two-dose exposure in a single shot, which could become ideal for mass vaccination campaigns,” Irvine says.

The researchers are now studying this vaccine strategy in a nonhuman primate model. They are also working on specialized materials that can deliver the second dose over an extended period of time, which could further enhance the immune response.

The research was funded by the Koch Institute Support (core) Grant from the National Cancer Institute, the National Institutes of Health, and the Ragon Institute of MIT, MGH, and Harvard.

“Therapies that use the patient’s immune system to fight their disease have a lot of potential to change how patients are treated. However, one of the biggest problems in the field right now is that these immunotherapies work well only in a small fraction of patients,” Elise Alspach, Ph.D., assistant professor of molecular microbiology and immunology at SLU, senior author on the paper.

Alspach and her team aimed to understand what determines good T-cell responses in patients, why some patients seem to have better T-cell responses than others, and why some patients respond well to immunotherapies. Research findings recently published in Cancer Immunology Research show that a protein called CXCL13 that has recently been linked to immunotherapy response in patients is more highly expressed in females than males. Additionally, Alspach and her team found that CXCL13 expression is a better marker of immunotherapy response in females than in males.

Alspach and her team used single-cell RNA sequencing in human datasets to understand more about differences in how male and female immune systems respond to tumors. Single-cell RNA sequencing allows scientists to learn what’s happening inside individual cells. Using this technology, Alspach and her team determined that T-cells that infiltrate female tumors are highly activated and ready to identify tumor cells and kill them. They also noted immune suppressive T-cells present more frequently in male tumors than in female tumors.

Alspach and her team discovered that there is growing evidence that the male sex is associated with a better response to immunotherapy, which she said appears to contrast with their work and recently published papers showing that females mount stronger immune responses against their tumors.

“We currently don’t understand why males would respond better than females to immune targeting therapies, but this interesting juxtaposition highlights the need for more research into the variable of sex in the immune response against cancer,” Alspach said.

Alspach said the potential of immunotherapy is revolutionary as it mediates tumor rejection in patients and induces long-term remission.

“When we get infected with a virus, the immune system generates a population of cells that can remember that virus and do a better job of eliminating it from your body, so the immune system does the same thing against tumors,” she said. “The memory response against that tumor partly generates long-term remissions that we see in patients treated with immunotherapies.”

Before the advent of immunotherapies, Alspach said cancer treatments were hard on the body and not tumor-specific or, in the case of small molecule drugs that targeted specific proteins inside tumor cells, frequently become resistant to therapies. Current immunotherapies are typically much better tolerated in more patients, and patients can maintain a higher quality of life because the immune system can be educated to specifically target the tumor rather than all the tissues in the body.

Because immune responses against tumors are different between the sexes, Alspach and her colleagues concluded that it makes sense to potentially design different treatments for male versus female patients. In the future, she hopes more appropriate therapeutic strategies will be devised to target the pathways that mediate better tumor control in ways that benefit individual patients.

This research was possible thanks to a recent investment in single-cell RNA sequencing technology at Saint Louis University, allowing researchers to bring us closer to new cures.

Additional authors include Richard J. DiPaolo, Ph.D.; Ryan M. Teague, Ph.D.; Michelle Brennan, Ph.D.; David DeBruin; Chinye Nwokolo; Katey S. Hunt; Alexander Piening; Maureen J. Donlin; and Stephen T. Ferris, Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine.

The approach, detailed in the journal Cell Stem Cell, uses patients’ own tumor cells that replicate the unique characteristics of a patient’s tumor allowing scientists to quickly screen a large number of drugs in order to identify personalized treatments that can target this rare and diverse group of cancers.

“Sarcoma is a rare and complex disease, which makes conducting clinical trials to identify effective treatments particularly challenging. Some of the rarer subtypes lack standard treatment altogether. Even when multiple therapy options are available, there is often no reliable, data-driven method to determine the best course of action for an individual patient. Choosing the most effective treatment is akin to searching for a needle in a haystack,” said Dr. Alice Soragni, the senior author of the study and assistant professor in the department of Orthopaedic Surgery at the David Geffen School of Medicine at UCLA. “Testing drugs with patient-derived tumor organoids has potential to help predict how a patient may respond to treatment, with the goal of improving patient outcomes for diseases where treatment options are often limited.”

While sarcomas, which can develop in the bones or soft tissues like muscles and adipose tissue, only account for less than 1% of all cancers, they carry a high mortality rate, particularly among young people. The rarity and diversity of sarcoma types — more than 100 distinct subtypes — makes them particularly difficult to study. Responses to conventional therapies can vary widely between patients, making it challenging to determine the most effective course of action for each individual.

To determine whether organoids could enhance the understanding of how a patient’s tumor might respond to specific drugs or combinations, the team assembled a biobank of 294 samples from 126 UCLA patients diagnosed with 25 different subtypes of bone and soft tissue sarcoma. While tumor organoids have been widely used to study carcinomas, this study is the first of its scale to extend organoid development to sarcoma.

The team successfully created tumor organoids from over 110 samples and conducted detailed histopathological and molecular analyses to confirm that the organoids retained the key characteristics of the original tumors. These organoids were then subjected to high-throughput drug screening using the mini-ring pipeline developed by Soragni and her team, enabling the testing of hundreds of drugs in a 3D format within a short timeframe.

Using this process, the team was able to identify at least one potentially effective U.S. Food and Drug Administration (FDA)-approved treatment for 59% of the samples tested. Additionally, they found the drug responses observed in the lab matched how the patients themselves responded to treatment for a small number of cases, suggesting that these organoids could be a powerful tool for guiding clinical decisions.

“We’ve shown that it’s possible to generate sarcoma organoids quickly — within a week after surgery or biopsy — and use them to screen a large number of drugs, including FDA-approved therapies and other treatments currently in clinical trials,” said Soragni.

“This gives us the ability to identify which drugs are most likely to work for a particular patient, which is crucial for a disease as complex as sarcoma, where genomic precision medicine has often fallen short,” added study author Dr. Noah Federman, the Glaser Family Endowed Chair and director of the UCLA Health Jonsson Comprehensive Cancer Center’s Pediatric Bone and Soft Tissue Sarcoma Program.

In addition, the study demonstrated that a large-scale, functional precision medicine program could be implemented within a single institution, offering a streamlined and scalable model for organoid-based testing.

“Organoids provide a tangible way to match patients with the most promising therapies and this could be a game-changer for sarcoma patients,” said Dr. Nicholas Bernthal, chair and executive medical director of the Department of Orthopaedic Surgery at UCLA. “We’re optimistic that this approach will lead to better, more personalized care for those who need it most.”

Following the results of this study, the UCLA team will validate the findings in a larger clinical trial that is aimed at confirming the effectiveness of the organoid-based approach in predicting treatment responses in patients with osteosarcoma, the most common type of bone cancer that mainly affects children and young adults.

Soragni, Federman and Bernthal are all members of the UCLA Health Jonsson Comprehensive Cancer Center. The study’s first authors are Ahmad Shihabi, a project scientist in the Soragni laboratory; Peyton Tebon, a visiting project scientist; and Huyen Thi Lam Nguyen, a graduate student. Other UCLA authors are Sara Sartini, Ardalan Davarifar, Alexandra Jensen, Miranda Diaz-Infante, Hannah Cox, Alfredo Enrique Gonzalez, Summer Swearingen, Helena Winata, Sorel Fitz-Gibbon, Takafumi Yamaguchi, Jae Jeong, Sarah Dry, Arun Singh, Bartosz Chmielowski, Joseph Crompton, Fritz Eilber, Scott Nelson, Paul Boutros and Jane Yanagawa.

The study was supported by grants from the National Cancer Institute, the Alan B. Slifka Foundation, David Geffen School of Medicine at UCLA and the UCLA Health Jonsson Comprehensive Cancer Center.

In findings published today (Sept. 19) in the Journal of Clinical Microbiology, the researchers report that the bacteria Salmonella enterica was detected in samples from two wastewater treatment plants in central Pennsylvania during June 2022.

“Non-typhoidal Salmonella is a common cause of gastroenteritis worldwide, but current surveillance for the disease is suboptimal, so in this research we evaluated the utility of wastewater monitoring to enhance surveillance for this foodborne pathogen,” said Nkuchia M’ikanatha, lead epidemiologist, Pennsylvania Department of Health and an affiliated researcher in Penn State’s Department of Food Science, in the College of Agricultural Sciences. “In this study, we explored wastewater monitoring as a tool to enhance surveillance for this foodborne pathogen. Wastewater testing can detect traces of infectious diseases circulating in a community, even in asymptomatic individuals, offering an early warning system for potential outbreaks.”

While health care providers are required to report salmonellosis cases, many go undetected. Salmonella bacteria, inhabiting the intestines of animals and humans, are shed in feces. The CDC estimates Salmonella causes roughly 1.35 million infections, 26,500 hospitalizations and 420 deaths annually in the U.S., primarily through contaminated food.

In June 2022, the researchers tested raw sewage samples collected twice a week from two treatment plants in central Pennsylvania for non-typhoidal Salmonella and characterized isolates using whole genome sequencing. They recovered 43 Salmonella isolates from wastewater samples, differentiated by genomic analysis into seven serovars, which are groupings of microorganisms based on similarities. Eight of the isolates, or nearly 20%, were from a rare type of Salmonella called Baildon.

The researchers assessed genetic relatedness and epidemiologic links between non-typhoidal Salmonella isolates from wastewater and similar bacteria from patients with salmonellosis. The Salmonella Baildon serovars isolated from wastewater were genetically indistinguishable from a similar bacteria found in a patient associated with a salmonellosis outbreak in the same period in the area. Salmonella Baildon from wastewater and 42 outbreak-related isolates in the national outbreak detection database had the same genetic makeup. One of the 42 outbreak-related isolates was obtained from a patient residing in the wastewater study sample collection catchment area, which serves approximately 17,000 people.

Salmonella Baildon is a rare serovar — reported in less than 1% of cases nationally over five years, noted M’ikanatha, the study’s first author. He pointed out that this research demonstrates the value of monitoring sewage from a defined population to supplement traditional surveillance methods for evidence of Salmonella infections and to determine the extent of outbreaks.

“Using whole genome sequencing, we showed that isolates of variant Salmonella Baildon clustered with those from an outbreak that occurred in a similar time frame,” he said. “Case reports were primarily from Pennsylvania, and one individual lived within the treatment plant catchment area. This study provides support for using domestic sewage surveillance in assisting public health agencies to identify communities impacted by infectious diseases.”

Ed Dudley, a professor of food science and the senior author on the study, said these findings highlight the potential of wastewater monitoring as an early warning system for foodborne disease outbreaks, potentially even before physicians and laboratories report cases. This proactive approach could enable health officials to swiftly trace the source of contaminated food, ultimately reducing the number of people affected, suggested Dudley, who also directs Penn State’s E. coli Reference Center.

“While it may not happen overnight, I foresee a future where many, if not most, domestic wastewater treatment plants contribute untreated sewage samples for monitoring evidence of various illnesses,” he said. “This would likely involve collaboration among public health agencies, academia and federal entities, much like our pilot study. I see this as yet another crucial lesson from the pandemic.”

Contributing to the research at Penn State were Jasna Kovac, associate professor of food science and Lester Earl and Veronica Casida Career Development Professor of Food Safety; Erin Nawrocki and Yezhi Fu, postdoctoral scholars in the Dudley Lab; Zoe Goldblum, undergraduate researcher in the Department of Food Science; and Nicholas Cesari, Division of Infectious Disease Epidemiology, Pennsylvania Department of Health.

The CDC, the U.S. Food and Drug Administration and the U.S. Department of Agriculture’s National Institute of Food and Agriculture provided funding for this research.