Among the first cells of the immune system to respond to microorganisms that invade our body are neutrophils.  Although neutrophils are considered the “good guys” in such circumstances, they also contribute to the noninfectious chronic inflammation that underlies various diseases, including autoimmune diseases such as rheumatoid arthritis.  One mechanism by which neutrophils protect us is to internalize microorganisms and destroy them using proteins known as neutrophil serine proteases (NSPs), but whether NSPs have a role in noninfectious chronic inflammation has not been clearly determined.  However, using mice lacking two very similar NSPs, PR3 and NE, a team of researchers at the Max-Planck-Institute of Neurobiology, Germany, have now shown that these two NSPs have a crucial role in one form of noninfectious chronic inflammation.  Detailed analysis revealed that PR3 and NE destroy an anti-inflammatory molecule known as PGRN and in this way help to promote inflammation in the absence of invading microorganisms.  The authors therefore suggest that these data provide rationale for considering inhibitors of NSPs as anti-inflammatory drugs.

Individuals inhale measles virus particles in aerosols and it is currently thought that these particles infect the cells that line the airways (respiratory epithelial cells) before being passed to immune cells that carry the virus particles to other parts of the body and then back to the airways, which again become infected and shed virus into exhaled aerosols.  In the study, a measles virus unable to bind to and infect epithelial cells was found to cause symptoms of measles virus infection in monkeys even though it did not infect respiratory epithelial cells and was not being shed into exhaled aerosols.  These data suggest that, in fact, inhaled measles virus particles first infect lymphocytes and are only passed to respiratory epithelial cells from the lymphocytes in the tissues.  Further, they indicate that the protein that measles virus particles bind to on respiratory epithelial cells, which has yet to be identified, is likely to be found on the surface of the cells that faces the tissues rather than the surface that faces the airways, as previously assumed.  As discussed in an accompanying commentary by Makoto Takeda, at Kyushu University, Japan, the results of this study should help researchers identify this protein.

Drugs known as HDAC inhibitors, which have antitumor activity and can be used to treat some forms of skin cancer and some types of leukemia, are also known to have anti-inflammatory properties, but the mechanisms by which they modulate the immune system have not been determined.  New data, generated by Pavan Reddy and colleagues, at the University of Michigan Cancer Center, Ann Arbor, have now indicated one mechanism by which HDAC inhibitors modulate the mouse and human immune system and the information gained has been used to develop an approach to protect mice from graft-versus-host disease after bone marrow transplantation.

In the study, two different HDAC inhibitors were shown to prevent mouse and human immune cells known as dendritic cells (DCs) from initiating proinflammatory immune responses in vitro.  Further, if Dcs treated ex vivo with HDAC inhibitors were injected into mice after they had received a bone marrow transplant, the incidence and severity of graft-versus-host disease was dramatically reduced.  Detailed analysis revealed that the HDAC inhibitors mediated their effects by inducing Dcs to express more of a molecule known as IDO, which is a suppressor of DC function.  The authors therefore hope that their data provide support for studies to determine whether HDAC inhibitors might be of benefit to individuals receiving bone marrow transplants and to those with other immune-mediated diseases.

A small molecule that locks an essential enzyme in an inactive form could one day form the basis of a new class of unbeatable, species-specific antibiotics, according to researchers at Fox Chase Cancer Center.

Their findings, highlighted on the cover of the June 23 issue of the journal Chemistry & Biology, take advantage of an emerging body of science regarding “morpheeins” – proteins made from individual components that are capable of spontaneously reconfiguring themselves into different shapes within living cells.

The researchers discovered a small molecule, which they have named morphlock-1, binds the inactive form of a protein known as porphobilinogen synthase (PBGS), an enzyme used by nearly all forms of cellular life.  The functioning form of PBGS is built from eight identical component parts – in what is called an octamer configuration – and is essential among nearly all forms of life in the processes that enable cells to use energy.  The other configuration is made of six parts – or a hexamer configuration – and serves as a “standby” mode for the protein.

“As the name suggests, morphlock-1 essentially locks the hexamer configuration into place, preventing its protein subunits from reconfiguring into the active assembly,” says lead investigator Eileen Jaffe, Ph.D, a Senior Member of Fox Chase.  “Targeting morpheeins in their inactive assemblies provides an entirely new approach to drug discovery.”

While their study was performed using a pea plant-version of PBGS, the researchers have reason to believe the principle could apply to bacterial versions of PBGS as well.  “Using morphlock-1 as a base, we are seeking to fine tune the molecule so that it blocks just the bacterial version of the PBGS enzyme, ” Jaffe says.

“Because PBGS is so crucial for life, the part of the enzyme where chemistry happens is highly conserved through evolution,” Jaffe says, meaning that an all-around PBGS-inhibiting drug would harm bacteria, peas and people alike.  The area where the potential drug binds to the hexamer form of the protein, however, has been found to differ among species, depending how far the organisms have evolved from each other.

When PBGS is in its inactive hexamer form, there is a small cavity on the surface of the assembled complex.  Using computer docking techniques, Jaffe and her Fox Chase colleagues identified a suite of small molecules predicted to bind to this cavity.

The researchers then bought and tested a selection of these molecules in the lab to see if any of them stabilized the pea PBGS in its hexamer assembly.  One inhibitor in particular, given the name morphlock-1, potently drove the formation of the hexamer in pea PBGS, but not in that of humans, fruit flies, or the infectious bacteria Pseudomonas aeruginosa, or Vibrio cholerae, the latter of which causes cholera.  Morphlock-1 is a potent inhibitor of pea PBGS, but not of the PBGS from these other organisms.

Jaffe coined the term “morpheein” in 2005 after a study of the structure of PBGS revealed its shape-shifting tendencies.  While initially met with skepticism because the existence of morpheeins contradicts some classic concepts about protein structure and function, subsequent studies have reinforced that PBGS (and perhaps other proteins) exhibits this behavior.  According to Jaffe, this study is the first to make use of alternate morpheein shapes as a potential strategy for drug discovery, in general, particularly for antibiotics.

“Multi-drug resistance drives the need for developing new antibiotics,” Jaffe says.  “Since drugs that stabilize the inactive PBGS hexamer need not be chemically similar to each other, it will be difficult for the bacterium to develop complete resistance to a cocktail of such compounds.”

Researchers from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the National Institutes of Health (NIH), have identified a promising new target for autoimmune disease treatment – a cell-surface receptor called DR3. Their research in mice, published on line in the journal Immunity, suggests that blocking this receptor could slow or stop the damaging inflammation characteristic of autoimmune diseases, potentially without leaving the body vulnerable to serious infections, as many current therapies do.

DR3 is a protein on the surface of cells. It is a member of the tumor necrosis factor (TNF) family of receptors, which bind to molecules related to TNF, a cell-signaling protein that promotes inflammation. Many of today’s most potent treatments for inflammatory diseases, such as rheumatoid arthritis and psoriasis, interfere with the action of TNF, thereby blocking inflammation. Since current anti-TNF therapies don’t work in all autoimmune diseases, however, the researchers turned to the study of DR3, which is a close relative of TNFR1, the main receptor for TNF.

Working with mouse models of asthma and multiple sclerosis, both immune system diseases, the researchers found that mice engineered to lack DR3 were resistant to those diseases. “The implication is that blocking DR3 in mice, and possibly in humans, is a potential therapy for these diseases and perhaps others in which the immune system goes awry,” said Richard Siegel, M.D., Ph.D., a scientist in the NIAMS’ Immunoregulation Group, who led the research effort.

While closely related to TNFR1, DR3 is expressed in T cells, a different kind of immune cell (a white blood cell that identifies and fights infection) than those that express TNFR1, Dr. Siegel said. The NIAMS group collaborated with a laboratory in Cardiff, Wales, which had generated genetically engineered mice deficient in DR3, as well as with a research group at the NIH’s National Institute of Allergy and Infectious Diseases (NIAID), which has developed mouse models of disease with strong T cell components, such as asthma and multiple sclerosis. “These findings open up new avenues for therapy of these two diseases as well as to other autoimmune diseases in which T cells play a role in causing or perpetuating the disease,” said Siegel.

The researchers hope that DR3-blocking agents will be effective anti-inflammatory treatments someday. Siegel noted that if they were to be used in rheumatic diseases, they would be a complement to strategies that block TNF because they hit a different arm of the immune system. “It could be potentially synergistic or complementary,” he said.

Of critical importance, the NIAMS scientists found that removing DR3 did not appear to suppress the immune response or the ability to fight infection within the mice – a problem with many other treatments for autoimmune disease. “We could see the effect of DR3 deficiency in the diseased organ, but when we looked systemically at the immune response at other places in the mouse, it was barely affected,” said Dr. Siegel. The group’s findings suggest that DR3-blocking agents might be more effective at specifically treating autoimmune disease without breaking down the body’s defenses against infections, a long-sought goal of researchers in the field.

The immune system of vertebrate animals consists of two components: the innate immune response, a constitutive system ready to respond to a pathogen, and the adaptive immune response, a system of immunological memory that responds to previously encountered pathogens. In a study led by Dr. Anlong Xu of Sun Yat-sen University, scientists searched the amphioxus genome for genes that may be relevant to immunity in order to gain an understanding of what the immune system repertoire of the vertebrate ancestor may have looked like. “Our chordate ancestors had a remarkably elaborate innate immune system, but this system was somehow reduced in the vertebrate lineage, which is unusual to our conventional thinking of the immune system,” explains Xu. Furthermore, Xu notes that this work helps to describe a global picture of innate immunity and uncover the evolutionary footsteps underlying the evolution of human immune pathways.

Scientists funded by the Biotechnology and Biological Sciences Research Council (BBSRC) have discovered how evolution may have lumbered humans with allergy problems. The team from the Randall Division of Cell & Molecular Biophysics, King’s College London are working on a molecule vital to a chicken’s immune system which represents the evolutionary ancestor of the human antibodies that cause allergic reactions. Crucially, they have discovered that the chicken molecule behaves quite differently from its human counterpart, which throws light on the origin and cause of allergic reactions in humans and gives hope for new strategies for treatment. The work is published today (13 June) in The Journal of Biological Chemistry.

Researcher, Dr Alex Taylor said: “This molecule is like a living fossil – finding out that it has an ancient past is like turning up a coelacanth in your garden pond. By studying this molecule, we can track the evolution of allergic reactions back to at least 160 million years ago and by looking at the differences between the ancient and the modern antibodies we can begin to understand how to design better drugs to stop allergic reactions in their tracks.”

The chicken molecule, an antibody called IgY, looks remarkably similar to the human antibody IgE. IgE is known to be involved in allergic reactions and humans also have a counterpart antibody called IgG that helps to destroy invading viruses and bacteria. Scientists know that both IgE and IgG were present in mammals around 160 million years ago because the corresponding genes are found in the recently published platypus genome. However, in chickens there is no equivalent to IgG and so IgY performs both functions.

Lead researcher, Dr. Rosy Calvert said: “Although these antibodies all started from a common ancestor, for some reason humans have ended up with two rather specialised antibodies, whereas chickens only have one that has a much more general function.

“We know that part of the problem with IgE in humans is that it binds extremely tightly to white blood cells causing an over-reaction of the immune system and so we wanted to find out whether IgY does the same thing.”

By examining how tightly IgY binds to white blood cells the researchers have found that it behaves in a much more similar way to the human IgG, which is not involved in allergic reactions and binds much less tightly.

Professor Brian Sutton, head of the laboratory where the work was done said: “It might be that there was a nasty bug or parasite around at the time that meant that humans needed a really dramatic immune response and so there was pressure to evolve a tight binding antibody like IgE. The problem is that now we’ve ended up with an antibody that can tend to be a little over enthusiastic and causes us problems with apparently innocuous substances like pollen and peanuts, which can cause life-threatening allergic conditions.”

The next stage of the work is to examine in very fine detail the interaction between the antibodies and the surface of the white blood cell. This is with a view to designing drugs that could alter this interaction and therefore ‘loosen’ the binding of IgE, making it more like its chicken counterpart.

Oral ingestion of pomegranate extract reduces the production of chemicals that cause inflammation suggests a study published in BioMed Central’s open access Journal of Inflammation. The findings indicate that pomegranate extract may provide humans with relief of chronic inflammatory conditions.

The group from the Department of Medicine of Case Western Reserve University, Cleveland Ohio, led by Tariq Haqqi, showed that blood samples collected from rabbits fed pomegranate extract inhibited inflammation.

Pomegranate extract is already used as a treatment in alternative medicine for inflammatory conditions, such as arthritis. Although pomegranate extract has antioxidant and anti-inflammatory actions in experiments on isolated tissues, it is not known whether ingestion of it can produce the same anti-inflammatory effects in living systems, either because the active compounds are not absorbed from the gut or because the levels of these compounds in the blood are not high enough.

Pomegranate extract, the equivalent of 175mls of pomegranate juice, was given to rabbits orally. The levels of antioxidants were measured in blood samples obtained after drinking the pomegranate extract and compared to blood samples collected before ingestion of pomegranate extract.

Plasma collected from rabbits following ingestion of pomegranate extract contained significantly higher levels of antioxidants than samples collected before ingestion of pomegranate extract; the extract also significantly reduced the activity of proteins that cause inflammation, specifically cyclooxygenase-2. It also reduced the production of pro-inflammatory compounds produced by cells isolated from cartilage.

The results of this study indicate the beneficial effects of pomegranate extract when ingested. According to Haqqi “the use of dietary nutrients or drugs based on them as an adjunct in the treatment of chronic inflammatory conditions may benefit patients”. He adds that, “Current treatment with anti-inflammatory drugs can have serious side effects following long-term use. Further research is needed, however, especially on the absorption of orally ingested substances into the blood.”

As tumors progress they develop ways to escape recognition and attack by cells of the immune system. However, the mechanisms by which tumors modify the immune system have not been clearly determined. New insight into the way in which chronic lymphocytic leukemia (CLL) cells limit immune cell attack has now been provided by John Gribben and colleagues, at Barts and The London School of Medicine, United Kingdom.

For immune cells known as CD4+ and CD8+ T cells to become activated they must contact other cells known as APCs. The area of contact is known as the immunological synapse and it is highly organized. In the study, CD4+ and CD8+ T cells from patients with CLL were found to exhibit defective immunological synapse formation with APCs. Further, if CD4+ and CD8+ T cells from healthy individuals were cultured with CLL APCs, they also showed defective immunological synapse formation. As treatment with an immune system–modifying drug improved immunological synapse formation, the authors suggest that approaches to overcoming immunological synapse defects might improve the efficacy of new ways to treat cancer that are currently being developed and that are based on enhancing the antitumor activity of CD4+ and CD8+ T cells.

Researchers at Duke University Medical Center have uncovered definitive evidence that a small but potent subset of immune system B cells is able to regulate inflammation.Using a new set of scientific tools to identify and count these cells, the team showed that these B cells can block contact hypersensitivity, the type of skin reactions that many people have when they brush against poison ivy.

The findings may have large implications for scientists and physicians who develop vaccines and study immune-linked diseases, including cancer. Once the cells that regulate inflammatory responses are identified, scientists may have a better way to develop treatments for many diseases, particularly autoimmune diseases such as arthritis, type 1 diabetes and multiple sclerosis.

“While the study of regulatory T cells is a hot area with obvious clinical applications, everyone has been pretty skeptical about whether regulatory B cells exist,” said Thomas F. Tedder, Ph.D., chairman of the Immunology Department and lead author of the study published in the May issue of Immunity. “I am converted. They do exist.”

Koichi Yanaba and Jean-David Bouaziz identified this unique subset of small white blood cells, which they call B10 cells, in the Tedder laboratory.

The researchers found that B10 cells produce a potent cytokine, called IL-10 (interleukin-10), a protein that can inhibit immune responses. The B10 cells also can affect the function of T cells, which are immune system cells that generally boost immune responses by producing cytokines. T cells also attack tumors and virus-infected cells.

The study was supported by grants from the NIH, the Association pour la Recherche contre le Cancer (ARC), Foundation Rene Touraine, and the Philippe Foundation.

Depleting B10 cells may enhance some immune responses, Tedder said. Enhancing B10 cell function may inhibit inflammation and immune responses in other diseases, like contact hypersensitivity.

“Now that we have been able to identify this regulatory B cell subset, we have already developed treatments that deplete these cells in mice. We are moving to translate these findings to benefit people,” he said.

“The discovery of the ability to identify this potent regulatory cell type should provide important clues to how the immune system regulates itself in response to vaccines as well as infectious agents,” says Barton F. Haynes, M.D., leader of the international Center for HIV/AIDS Vaccine Immunology (CHAVI), a consortium of universities and academic medical centers, and director of the Duke Human Vaccine Institute. “This information should enable researchers to design ways to help the immune system control infections more effectively, and could be a useful advance as we refine approaches to preventing HIV infection.”

There’s a huge initiative underway to look at regulatory T cells in autoimmune disease, HIV infection, and cancer therapy,” Tedder said. “What we have also shown is that it is not only regulatory T cells, but also regulatory B cells that could prevent a person from making effective immune responses in HIV and many other diseases, particularly cancer.”

The Duke researchers developed a way to mark the B10 cells so that they could see that just these cells were producing IL-10. Previously, scientists could only purify a population of B cells and see whether IL-10 could be produced by some of these cells in the population.

In this study, they found that the B10 cells represented only 1-2 percent of all of the B cells in the spleen of a normal mouse. Before this, no one had definitively identified this B cell subset or such regulatory B cells in normal mice, although B cell regulatory function had been described in some genetically altered mice with chronic inflammation.

“In this study, we could directly look at the B cells that were producing IL-10, and figure out what their cell surface molecules looked like, so that we could isolate them. This allowed us to show that this rare subset of B cells controlled immune responses by producing IL-10, which inhibits T cell inflammatory responses,” Tedder said.

The scientists studied a special mouse (CD19-deficient) with altered genes that give them an increased contact hypersensitivity reaction. As it turned out, these mice lacked B10 cells, which resulted in exaggerated inflammation reaction. “This allowed us to show that giving CD19-deficient mice a few B10 cells had a big effect on reducing inflammation,” Tedder said.

They found that depleting all B cells in the mice also resulted in worse inflammation. Since total B cell depletion therapies are now being used to treat people with B cell cancers and autoimmune disease, these findings help to further explain how these therapies treat disease. They also open the door to creating new therapies that take advantage of the power of B10 cells.

This is the first of several papers that will describe cases in which regulatory B10 cells help control immune responses, Tedder said.

Scientists at Saint Louis University have made two key discoveries that could lead to the first-ever human testing of a drug to target the adenovirus, which causes a number of severe upper-respiratory infections and is one of many viruses that causes the common cold.There are currently no drugs approved specifically to treat adenovirus infections in large part because there has been no animal model in which to test drug candidates, a key prerequisite before testing in humans.

SLU researchers and their collaborators, however, have made two breakthrough findings: an animal model suitable for adenovirus testing – in this case using Syrian hamsters – and a drug that successfully attacks the adenovirus in those animals. The drug, hexadecyloxypropyl-cidofovir or CMX001, is currently under development by Chimerix, Inc. as a biodefense agent to meet the threat of smallpox or monkeypox viruses and as an antiviral agent in transplant patients.

The SLU research is published the week of May 19 in an early online edition of the Proceedings of the National Academy of Sciences.

“This is exciting news and a major step forward in finding a drug to treat adenovirus infections in humans,” said William Wold, Ph.D., professor and chair of the department of molecular microbiology and immunology at the Saint Louis University School of Medicine and the study’s lead author.

One of the key obstacles to finding an animal model for adenovirus testing involves the fact that the virus is generally species-specific; meaning the human version of the virus doesn’t replicate well in animals commonly used in laboratory research.

The SLU researchers, however, found that the adenovirus replicates in Syrian hamsters (also called golden hamsters) with suppressed immune systems in much the same manner as it replicates in humans whose immune systems are weakened – making Syrian hamsters ideal for animal model testing.

“We are pleased to see that CMX001, a drug candidate showing broad antiviral activity that is being developed under a federal grant for smallpox, also has potential benefit against adenovirus,” said George R. Painter, Ph.D., president and CEO of Chimerix.

Said Samuel Stanley Jr., director of the Midwest Regional Center of Excellence for Biodefense and Emerging Infectious Diseases Research (MRCE): “It is exciting to see work funded by the National Institute of Allergy and Infectious Diseases’ MRCE program lead to potential new therapies for this important virus.”

There are 52 known serotypes, or strains, of adenovirus in humans. They generally cause acute upper respiratory infections including colds, tonsillitis and ear infections, but they can also cause conjunctivitis, gastroenteritis and bladder infections.

Most people are able to recover from an adenovirus infection, but in some young children and people with weakened immune systems, adenovirus infections can turn virulent and even deadly. Adenovirus can also cause disease and even death in organ transplant recipients. Severe adenovirus outbreaks have occurred among groups of military recruits likely due to crowded living conditions.

CMX001 is an oral pro-drug, or derivative, of cidofovir, a drug developed by Gilead Sciences, Inc. to treat a type of retinitis in AIDS patients. Chimerix licensed from Gilead the rights to develop CMX001.

Cidofovir has long been a possible candidate to treat a number of virus infections, including the herpes virus, poxvirus and adenovirus infections in humans. The drug, however, is quite toxic to the liver and kidneys and is not available in oral form, which limits widespread use.

Using the new animal model, the SLU researchers found that CMX001 provided protection from the adenovirus when it was administered prophylactically (before infection with the virus) or therapeutically (after infection). The scientists found that the drug worked by greatly reducing the ability of the virus to replicate in key organs, mostly notably the liver.

The SLU team also found that CMX001 was much less toxic and far more powerful than cidofovir. In addition, scientists discovered, two weeks after infection with the virus CMX001 had reduced the viral load in the liver and blood to undetectable levels.

High living standards and the life style connected to them seem to promote the development of autoimmune diseases and allergic symptoms. This has lead to the assumption that the immune system begins to overreact to the organism’s own structures or to exogenous non-infectious proteins, i.e. allergens, when it does not have to work hard enough to protect the individual from infections.

The European Union with its Seventh Framework Program has allocated 6 million euros to the University of Helsinki coordinated DIABIMMUNE research project for the years 2008-2013 to establish whether the decrease in the infection load is connected to type 1 diabetes and the emergence of allergies.

The project comprises 12 partners from five countries. The study will include 7 000 children from Finland, Estonia and Russian Karelia in northwestern Russia. In each country the study will follow more than 300 children from birth to their 3rd birthday. In addition, the research will focus on 2 000 children from their third to fifth birthdays.

“Earlier we have studied autoimmune phenomena and allergic responses in Finnish and Russian Karelian school children. Now we are to study infants and toddlers in order to yield new information on the maturation of the immune system and the interaction between the immune system and the environment”, says Professor Mikael Knip from the University of Helsinki.

Based on earlier studies it is known that the incidence of type 1 diabetes is six times higher and the prevalence of celiac disease five times higher among Finnish children than among Russian Karelian children. The HLA gene variants that predispose people to autoimmune diseases are however approximately equally common in both populations. The studies have also revealed that Russian Karelian school children have helicobacter antibodies as signs of earlier infections 15 times more often, Toxoplasma antibodies five times more often, and hepatitis A antibodies 12 times more often than Finnish children. Karelian children also have considerably more often antibodies against the Coxsackie B4 virus, belonging to the enterovirus group, than Finnish children have.

“The differences in the frequency of autoimmune phenomena and allergic responses between Finland and Russian Karelia cannot be due to genetic causes. High living standards and the associated life style appear to promote the development of autoimmune diseases and allergic responses”, Knip says.

The DIABIMMUNE project focuses for example on the development of the intestinal bacterial flora after birth and the effect the living environment has on the composition of the bacterial flora. The research also studies the effect infections have on the maturation of the human immune system and the operation of the white blood cells that regulate immune responses. In addition, the researchers study whether the protection conferred by infections against autoimmune and allergic responses is associated with the overall infection load or due to specific microbes. The project also examines the effect of the child’s nutrition on the maturation of the immune system, the intestinal bacterial flora and the occurrence of infections.

“The diseases we are studying are the most common chronic diseases in children and their impact, both societal and medical, is vast. We are searching for ways to stop these diseases from becoming more frequent and to prevent their development”, Knip says.