Countering ‘Memory Loss’ In The Immune System

On December 26, 2010, in Immunology, by Christopher Fisher, PhD


After recovering from a cold or other infection, your body’s immune system is primed to react quickly if the same agent tries to infect you. White blood cells called memory T cells specifically remember the virus or bacterium and patrol the body looking for it. Vaccines work on the same principle: Harmless fragments of a virus or bacterium provoke the immune system to generate memory T cells that can attack the real thing later on.

As time passes, however, this specific immunity can wear off. That is because not all memory T cells live long enough to foster long-term immunity.

MIT biologists have now demonstrated the conditions that favor development of long-term memory T cells over short-term memory T cells, which can respond quickly but do not stick around for very long after the initial infection. That discovery could help vaccine designers better tailor their formulas to elicit long-term memory immunity, says Jianzhu Chen, MIT professor of biology and member of the David H. Koch Institute for Integrative Cancer Research.

Chen and Herman Eisen, emeritus professor of biology, are senior authors of a paper on the work that appeared in the Proceedings of the National Academy of Sciences the week of Dec. 13.

In the PNAS study, the MIT team looked at mice infected with influenza. In mice, as in humans, influenza virus stimulates T cells, whose job is to kill infected cells. Every T cell is programmed to recognize different foreign proteins (also called antigens) located on the surfaces of infected cells. When a T cell binds to the antigen, the T cell becomes activated and starts rapidly reproducing, creating an army of cells that can identify and destroy the invader.

Once the infection is eliminated, most of the activated T cells die off, but a few of them stick around, in case the virus comes back. These are short-term memory T cells. Because they have already battled the virus and reproduced many times, they survive only weeks or months after the initial infection. (T cells can only divide a certain number of times before they die.)

A set of long-term memory T cells also develops during infection. These cells are programmed differently, so they can persist for decades. Recipients of the smallpox vaccine, for example, have been shown to still have T cells against the virus up to 70 years later, says Eisen.

Until now, it has been unclear how these different cell types develop. In their new study, Eisen and Chen investigated the role three factors: T-cell location, the amount of antigen exposure, and length of exposure.

Scientists already knew that T cell contact with a large amount of virus provokes development of short-term memory T cells, says Eisen. Chen and colleagues discovered that large amounts of antigen also suppress development of long-term memory T cells. Those cells only develop when exposed to a small amount of the antigen for a short period of time.

For example, if you have an infection in the respiratory tract, nearby T cells will be exposed to many viruses and become short-term memory cells. Those cells hang around the respiratory tract, ready to pounce quickly if the same virus re-infects you, but they eventually die off.

In more distant parts of the body, T cells are exposed to only small amounts of the virus, and some of those cells become long-term memory T cells specific to that virus. These maintain a low level of constant vigilance in case the virus ever returns.

Ulrich von Andrian, professor of immunopathology at Harvard, says the new study’s major contribution is its experimental support of existing theories. “It builds on ideas that have been around for a while, that were not rigorously tested by experiments, for the most part,” says von Andrian, who was not part of the research team.

When developing vaccines, the goal is usually to generate a stable population of long-term memory T cells. This study suggests that the best way to do that is to give a small amount of antigen, and, for vaccines that require multiple injections, not to give them too frequently.

“The general rule of thumb is that you don’t want to give a large amount of antigen on a short-term basis,” says Chen. He adds that the amount of antigen for inducing a long-term memory T cells likely varies depending on the route of immunization and the form of antigen, and so the dosage for each vaccine will have to be determined through experiments.

He says the findings will likely not impact flu-vaccine design because existing dosages have already been optimized over many decades. However, the findings should be applicable to vaccines now under development for other diseases, such as HIV, tuberculosis and dengue fever, says Chen.

Material adapted from MIT.

Addiction during the holidays: Recovered or not, it’s important to be prepared

by Adi Jaffe


The holidays are a stressful time for everyone. Between gift-giving, travel, and keeping up with all parts of the ever-complicated modern family unit, nearly anyone can find themselves driven towards the nearest coping mechanism, whatever that may be. However, for recovering addicts, or those still struggling with an active addiction, the holidays can be a particularly troubling season that can invite a destructive relapse. As with all mental and physical health issues, education and awareness are a powerful first line of defense. By going over some of the most frequently asked questions about addiction and the holidays, we can attempt to shed some light on these issues for addicts and their families to help combat them before, not after, they become bigger problems (like a relapse).

Why Are The Holidays So Difficult For Addicts?

Obviously, as just mentioned, the pressures of the holidays are difficult for everyone. But for addicts, these same issues of money, family and general stress are amplified, often because they are the same age-old issues that lie at the root of the addiction and the beginning of drug use and abuse in the first place. If the recovering addict has not had the opportunity to openly confront family issues in the past, either with the family itself or with a therapist or counselor, the potential for relapse can be great. A vast amount of research shows how stress can bring even long-dormant behavior back to the surface, which should serve as a warning to substance and behavioral addicts alike (like sex addicts or compulsive gamblers). On the other end of the spectrum, addicts without a stable family or group of friends are often left feeling alone and isolated during the holidays, another powerful source of the shame and boredom that can drive addictive behavior.

What Are Some Of  The Hidden Struggles That Can Intensify Addiction/Trigger A Relapse?

Most often, these struggles emerge from one of two likely scenarios. In the event of a still active addiction, attempts to hide the problem from friends and family and the resulting stress can, paradoxically, intensify the addictive behavior. And whether the addiction has been treated or not, gathering with family in a familiar place can frequently cause someone to face many of the underlying issues that can be the root causes of a drug addiction or compulsive behavior. To paraphrase Tolstoy, all unhappy families are unhappy in their own unique way, and whether one’s particular family is overly judgmental, enabling, angry, or whatever else, it can serve to restart self-destructive patterns of behavior. For some recovering addicts, there may be a family-imposed secrecy around the recovery itself, which can be trying at a time when the whole family is gathering, ostensibly to celebrate one another. Even the house (including the room where an addict used to act out) and certain family members (like that cousin they used to smoke weed with) can be important cues that may re-trigger cravings and old behavioral patterns. Additionally and importantly, if there is a family history of any kind of past abuse, this can obviously serve as a particularly powerful and insidious trigger for addicts, whether recovering or not. In fact, recent research suggests that these old, root stimuli may be much more powerful for drug addicts than re-experiencing the drug itself.

What Are Some Strategies For Surviving The Holidays?

First and foremost, one must be prepared. Since most people at least know and are aware of the potential issues that might arise within their own families, it is crucial not to try to “wing it.” If you know that your family is going to be asking lots of uncomfortable questions, practice some appropriate answers and don’t feel obligated to discuss any aspect of your recovery that you’re not comfortable discussing. If your family is overly focused on achievement or likes to bring up stories from the past that are triggering or shameful, rehearse your reactions to them. If you have a friend or significant someone who can help, do a little role-play trying out different answers and see how they feel as you actually say them out loud. It will never be exactly the same as you practice, but being prepared can go a long way towards taming the body and brain’s natural stress responses. Just as importantly, if you know you’re liable to encounter events or people that formerly facilitated addictive behavior, role play those likely scenarios and know how you plan on turning down or avoiding those substances or behaviors. For instance, figure out how exactly you’re going to tell your cousin you aren’t going to smoke in the basement with him before you have to actually do it. It will sound a lot less forced and strange the second time around and you will have already experienced some of the associated anxiety. If you’re going to be alone, make distinct plans for your activities and do the best you can to find healthy situations to participate in, even if they seem new or slightly uncomfortable at first. For instance, go ahead and join that group of strangers for a Christmas eve dinner or Christmas day movie instead of spending those times along. After all, uncomfortable or not, a new, healthy experience will be vastly preferable to sliding back into the same old destructive patterns of the past.

Should I Use New Years To Confront My Addiction?

Most everyone is familiar with the New Year’s Resolution as a method of planning major life changes. Of course, most everyone is also familiar with the limited success rate of these resolutions, and of the effectiveness of “going cold turkey” in general. Depending on the addiction, there are certainly things that individuals can do to help themselves- for example, research suggests that when trying to quit smoking setting a quit date and beginning to use replacement patches or supplements in anticipation of that date (in other words, while still smoking) can help reduce the amount of smoking while approaching that quit date, making it easier when the day finally arrives. If you’re planning to quit a “harder” drug than nicotine, you may want to set a whole schedule for reducing drug use prior to the quit date itself. The important thing is to be completely realistic in order for the change to stick. If you’re drinking a bottle of vodka a day, attempting to go completely dry within a week can be extremely dangerous to your health, and will not likely result in a permanent change. Once again, education and preparation are key. Prepare for any sort of quitting by looking online on sites like AllAboutAddiction and WebMD, and identify the medical and psychological issues that are likely to accompany your attempt. Look to see if your problem is one that you can handle alone, or if it is recommended that a doctor help you with the process. Remember that your goal should be lifetime change, not a temporary one. Though it might seem counter-intuitive, if your holidays promise to be especially difficult or stressful, you may want to hold off on trying to quit during them and look at them as a time to lay the groundwork for your post New Year quit attempt rather than going for a full on cold turkey try. Such pragmatism may well help you achieve your true goal.

Placebos Work Even When Patients Know They’re Dummy Pills

By Iris Tse, MyHealthNewsDaily contributor


For years, placebos have been valued for their supposed ability to do nothing — unlike medications with active ingredients, placebos derive their healing ability psychologically, by fooling patients into thinking they’re receiving a “real” drug.

However, a new study shows that placebos can offer effective treatment even when patients know they’re taking a so-called “dummy pill.”

Among patients with irritable bowel syndrome (IBS), 59 percent of those who knowingly took a placebo pill said their symptoms were adequately relieved after three weeks, while just 35 percent of patients who took no pills reported such relief.

“We were surprised by how effective the placebo pills were,” said study researcher Ted Kaptchuk, an associate professor of medicine at the Harvard Medical School.

In most drug studies, a treatment that works 20 percent better than the control is seen as statistically significant and clinically meaningful. “But here, you have something that is almost two-folds better,” Kaptchuk said.

In fact, the study showed the effects of the placebo pills were comparable to the effects of the powerful, but risky, IBS medication alosetron (sold under the brand name Lotronex).

“And most importantly, the placebo pills worked even when the patients know they were taking placebo pills and not real drugs,” Kaptchuk told MyHealthNewsDaily.

The researchers gave 80 patients with irritable bowel syndrome two treatments. One group, the control group, received only consultations with doctors and nurses. The second group received the same consultations and inert microcyrstalline cellulose pills, which were clearly labeled as “placebos,” and were told to take them twice a day.

Other placebo researchers said the results were interesting.

“Our current understanding is that, in order for placebos to work, patients have to believe strongly that the placebo is a real, active drug,” said Damien Finniss, a researcher at the University of Sydney who was not involved in this study.

“But this challenges our thinking. This shows that some form of placebo effect still exists, and can still have a powerful positive effect, even when patients know they’re not taking an active drug,” Finniss said.

Kaptchuk said he and and his colleagues conducted the study when a previous study showed that as many as 50 percent of American physicians gave placebos to unsuspecting patients because patients respond so well to them.

“All too often, patients in clinical trials worry that when they’re given the placebo, they won’t receive proper treatment. We want to learn more about placebos, and this is our way of measuring the effects with total transparency, trust and informed consent,” Kaptchuk said.

However, Kaptchuk said that while more research will be needed to replicate the findings in a larger group of patients, the study has advanced placebo research.

“Armed with this knowledge, we now know that we can measure the power of placebos in a responsible way in future trials and treatments, without having to deceive the patients and leading them on.”

The findings were published today (Dec. 22) in the journal PLoS ONE.

Four ways to avoid getting sick during the holiday season

By Madison Park, CNN


(CNN) — The Badger family holidays are filled with medical catastrophes.

One year, Melissa Badger’s niece stopped breathing at the Thanksgiving table because of a strep infection. In 2003, Badger’s son came down with a severe fever and ended up in the emergency room on Christmas. On Christmas Eve 2005, Badger tripped on ice while delivering presents to needy families and sprained her ankle.

This year, Badger’s husband complains of cold-like symptoms — fatigue, coughing and a sore throat. Badger struggled with a bug going around her office that was giving everyone stuffy noses and cold symptoms.

“Now, we get to worry about that lingering cold all of us have, since we’re hosting family this Christmas Eve,” said Badger. Hosting family means more than 30 people at their Beloit, Wisconsin, home.

Illness for many of us seems to knock at the most inopportune moments — after finishing a year-end project, before a holiday or after taking exams.

It had Shannon Duffy, who spent this Thanksgiving in bed with the flu, asking: “Is too much excitement and anticipation of the holiday season a bad thing? Or is it that my immune system just gets so overloaded with life stresses that when I step back and take a break, it is like an open invitation for the flu bug to intervene?”

With Mom sick in bed, Duffy’s sons had to microwave their TV dinners for Thanksgiving.

“I’ve been sick a lot during the holidays,” said the Palm Springs, California, resident. “If it’s not Thanksgiving, it’s Christmas.”

There are a few theories why sickness comes at the worst time.

“The holidays are a virus-distribution system,” said Dr. William Schaffner, chair of the department of preventive medicine at Vanderbilt University. “They help us distribute the viruses, influenza and other common cold virus from person-to-person because of close contact.”

1) Achoo to you, and you, and you

Flu season reaches its height in late fall and early winter. This is because viruses circulate better in the colder weather, said Dr. Philip Tierno, director of microbiology and immunology at New York University’s Langone Medical Center.

It’s not only cold and flu bugs that become active during colder seasons. CDC: Seasonal FluView

Other viruses, such as the norovirus and rotavirus, become more active during winter. Norovirus, known as the stomach flu, easily spreads through contamination in food, drink and surface contact. The virus is found in the stool and vomit of infected people. Rotavirus also causes diarrhea, vomiting, fever, and abdominal pain.

Advice: If you’re sick, cough into the crook of your arm.

If someone is coughing or wiping his or her nose, don’t hug or kiss the person. Use common sense, Tierno said.

5 Immunity boosting tips for moms

2) The sea of humanity … at the mall

Think of the holiday traditions: catching a show, shopping at a crowded mall, attending holiday parties.

All this means you’re indoors in crowds and exposed to everyone’s germs. As people cluster indoors, they use the same doorknobs, banisters and surfaces after wiping their noses or sneezing.

“During the winter season, we’re more subject to crowding, touching something that’s not hygienic and crowding,” Tierno said.

People get less fresh air, too.

“They don’t open up windows to get fresh air. They don’t go outside as much during cold weather. They decide to stay in, so any virus that may be present would be more easily spread,” he said.

Advice: Practice frequent hand-washing (at least 20 seconds wiping both the top, bottom of hands and between the fingers prior to eating and drinking) or use hand sanitizers.

Occasionally open the window to let fresh air circulate.

Must-know winter health & safety tips

3) Germs fly free

Air travel means if there’s a small flu outbreak on the West Coast, that virus could be in New York in less than five hours.

“Human travel is synonymous with virus travel,” said Shaffner, an infectious disease expert.

When family members travel across the country, they’re bringing along pathogens that have been in their communities and exposing them to new places.

It’s not only the act of being in an enclosed cabin of a car, bus, train or plane, Shaffner said.

“Remember we’re talking about being on an airplane, getting to the airplane, making your way through the crowds and other crowds in the other end,” he said. “It is just as important as the airplane.”

Advice: The Centers for Disease Control and Prevention recommends everyone older than 6 months old be vaccinated for influenza. Get your flu vaccine to reduce chances of getting sick.

Dr. Sanjay Gupta talks to Sebelius about flu shots

4) You’re super-stressed before vacation

End-of-the-year projects, reports, final exams — it could be all that work before break that spikes a stress hormone in your body.

“The increased cortisol level induces likelihood of infection during the holidays,” said Dr. Robert Hasty, assistant professor of internal medicine at Nova Southeastern University’s medical school.

Cortisol is a natural hormone that responds to stress, lowering immunity and making you more susceptible to infections.

The interval between acquiring a virus and becoming sick takes about 48 to 72 hours. You may have become infected when you were stressed and the symptoms may start to show right when you go on holiday break.

Advice: Stress might be unavoidable, but try getting enough sleep and hydrating.

Prevent the stress hormones from wreaking havoc by better planning, avoiding traffic, buying presents earlier.

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Music Fires Up Emotions in the Brain

By RICK NAUERT PHD Senior News Editor
Reviewed by John M. Grohol, Psy.D. on December 21, 2010


In a new study using brain imaging, researchers have identified how key aspects of musical performance cause emotion-related brain activity.

Edward Large, Ph.D., the study’s principal investigator, and Heather Chapin, Ph.D., the lead author, believe that their study pinpoints how musical performances charge up the brain’s emotional centers, and said that their technique will lead to new ways of studying responses to music and other emotional stimuli.

The researchers first recorded an expert musician’s performance of Frédéric Chopin’s Étude in E-Major, Op. 10, No. 3 on a computerized piano (the “expressive” performance), then they synthesized a version of the same piece using a computer, without the human performance nuances (the “mechanical” performance).

Both versions had the same musical elements — melody, harmony, rhythm, average tempo and loudness — and both were recorded on the same piano.

But only the expressive performance included dynamic changes in tempo and loudness, the performance variations that pianists use to evoke emotional responses. In the listening study, Large and Chapin used participants with an affinity for music.

They combined behavioral analysis with fMRI neuroimaging, a specialized MRI scan which measures change in blood flow related to neural activity in the brain, as participants listened to both performances. The listening study was conducted in three parts.

First, participants reported their emotional responses in real-time using specialized computer software. Immediately after providing their emotion ratings, they were placed in the fMRI and instructed to lie motionless in the scanner with their eyes closed and asked to listen to both versions of the music without reporting their emotional response. Immediately following the fMRI, they performed the emotion rating assignment again.

“We deliberately implemented these three steps in our study to ensure the consistency of the emotions our participants reported in the behavioral study with the results of the fMRI,” said Large.

The fMRI served as a critical tool to examine which areas of the brain “lit up” in response to the music. The analysis of brain activity compared responses to the expressive performance with responses to the mechanical performance, and responses of experienced listeners with those of inexperienced listeners. It also compared the tempo changes of the performance to the brain activations of listeners in real-time.

The results from this study have confirmed the hypothesis that the human touch of an expressive performance by a skilled pianist evokes emotion and reward-related neural activity. Furthermore, musically experienced listeners were found to have increased activity in the emotion and reward centers of the brain.

“Our experienced listeners were not professional musicians, but did have experiences performing music, such as singing in a choir or playing in a band,” said Large.

“The fMRI data suggests that experienced listeners get a greater charge out of the music, although we can’t say from this data whether the increased neural activation is due to their experience or whether these individuals seek out musical experiences because they derive greater pleasure from music.”

Perhaps most interestingly, the results also revealed neural activity that followed performance nuances in real-time.

These activations occurred in the motor networks of the brain that are thought to be responsible for following the beat of the music and in the brain’s mirror neuron system. The human mirror neuron system appears to play a fundamental role in both understanding and imitating action. This system is “fired up” when someone observes an action they can do being performed by someone else.

“It had previously been theorized that the mirror neuron system provides a mechanism through which listeners feel the performer’s emotion, making musical communication a form of empathy,” said Large. “Our results tend to support that hypothesis.”

The study is published in the journal PLoS One.

Source: Florida Atlantic University