Research Roundup: How COVID-19 Vaccines Train T Cells and More Research News

Antibodies

The immune system is made up of much more than antibodies. Although most of the news about the effectiveness and endurance of COVID-19 vaccines has focused on antibody titers, not as much has been reported on their effect on other parts of the immune system that offer longer-term protection, such as T cells. For that and more, continue reading.

4 Vaccines Teach T Cells to Fight the Omicron Variant of COVID-19

Investigators at La Jolla Institute for Allergy and Immunology found that four COVID-19 vaccines—the Pfizer-BioNTech, Moderna, Johnson & Johnson/Janssen and Novavax all caused the immune system to create effective, long-lasting T cells against SARS-CoV-2. They can also recognize other variants of concern, including Delta and Omicron. All the data was in fully vaccinated adults who had not yet received booster shots. The research team plans to investigate T-cell responses in people who received booster shots and those who have had the so-called “breakthrough” infections. That means they were vaccinated but were infected anyway. One finding was that fully vaccinated individuals have fewer memory B cells and neutralizing antibodies against the Omicron variant, consistent with early reports from other laboratories about waning immunity.

Most studies about the long-lasting effectiveness of vaccines have focused only on antibody responses. But this is only a part of the human immune response.

Dr. Alessandro Sette, professor and co-leader of the study, said, “The vast majority of T-cell responses are still effective against Omicron.

“These cells won’t stop you from getting infected,” said Dr. Shane Cortty, LJI Professor, “but in many cases, they are likely to keep you from getting very ill.”

This appears true for all the vaccines studied and for up to six months after vaccination. The relative lack of neutralizing antibodies does suggest that the Omicron variant is more likely to cause a breakthrough infection. Additional neutralizing antibodies are created slower with fewer memory B cells.

“Most of the neutralizing antibodies, i.e., the antibodies that work well against SARS-COV-2, bind to a region called the receptor binding domain, or RBD,” said LJI instructor Dr. Camila Coelho, who was co-first author of the study. “Our study revealed that the 15 mutations present in Omicron RBD can considerably reduce the binding capacity of memory B cells, compared to other SARS-CoV-2 variants such as Alpha, Beta and Delta.”

Treating Alzheimer’s Using Ultrasound Stimulation

Researchers at the Gwangju Institute of Science and Technology (GIST) in South Korea utilized external ultrasound pulses at gamma frequency to reduce protein accumulation in the brain. The technique involves syncing a person’s (or animal’s) brain waves above 30 Hz, called gamma waves, with an external oscillation of a given frequency. Earlier work in mice showed that this technique, gamma entrainment, could slow the formation of beta-amyloid plaques and tau proteins. The GIST group demonstrated it was possible, in mice, to apply the technology using ultrasound pulses at 40 Hz. The mice exposed to ultrasound pulses for two hours a day for two weeks had decreased beta-amyloid plaque concentration and tau protein levels in the brain. Electroencephalographic data on the mice showed functional improvements and did not cause micro bleeding.

2 Blood Proteins Point to Poor Longevity and Health

Scientists with the University of Edinburgh analyzed data from six large genetic studies into human aging, each of which held genetic data on hundreds of thousands of people. They analyzed 857 proteins and identified two that had significant negative effects across various measures of aging. People with genes that resulted in increased levels of these proteins were frailer, had poorer self-rated health, and were less likely to live exceptionally long lives. The first protein is apolipoprotein (LPA), which is believed to be involved in blood clotting. High levels of LPA increase the risk of atherosclerosis, resulting in heart disease and possible stroke. The second is vascular cell adhesion molecule 1 (VCAM1), primarily found on the surface of endothelial cells that line blood vessels. These control the expansion and retraction of blood vessels involved in blood clotting and the immune response.

Some Genes Protect the Obese from Some Diseases

Although obesity is, in general, bad for your health, some people with obesity seem to stay relatively healthy. Adiposity is related to how fat is distributed throughout the body. For example, fat under the skin, like a paunch or double chin, appears less harmful than fat stored around organs like the heart and liver. And it is genes that determine how and where the fat is stored. Geneticists at the University of Exeter used a technique dubbed Mendelian randomization. Of the 37 diseases they tested, they found that 12 were directly associated with genes that determine if a person has a “favorable adiposity.” The 12 included coronary artery disease, stroke and type 2 diabetes. Nine other diseases were classified as unrelated to adiposity and were probably due to carrying too much weight, such as deep vein thrombosis or arthritis in the knees. However, they point out that regardless of favorable or unfavorable adiposity, obesity is a serious risk to an individual’s health, and even obese people with favorable adiposity are at increased risk for diseases such as gallstones, adult-onset asthma, and psoriasis. On the other hand, they also found that some conditions that were thought to be associated with weight, such as Alzheimer’s, didn’t seem to be.

Super Immunity Against COVID-19

A laboratory study out of the Oregon Health & Science University identified two types of immunity against COVID-19: breakthrough infections after vaccination or natural infection after vaccination. They both provide approximately equivalent levels of enhanced immune protection. The so-called “super immunity” was previously used to describe very high levels of immune responses after breakthrough infections. The new research leveraged multiple live SARS-CoV-2 variants to assay cross-neutralization of blood serum from breakthrough cases. Essentially, the study found either are good at providing “super immunity” and the likely reason there are so many cases of breakthrough infections is that the virus is present in so much of the population.

“It makes no difference whether you get infected-and-then-vaccinated, or if you get vaccinated-and-then-a-breakthrough infection,” said Dr. Fikadu Tafesse, co-senior author and assistant professor of molecular microbiology and immunology in the OHSU School of Medicine. “In either case, you will get a really, really robust immune response—amazingly high.”

The problem, of course, is that both cases require you to get infected. Dr. Marcel Curlin, senior co-author and associate professor of medicine (infectious diseases) in the OHSU School of Medicine and director of OHSU Occupational Health, noted, “Immunity from natural infection alone is variable. Some people produce a strong response and others do not. But vaccination combined with immunity from infection almost always provides very strong responses.”

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