Imaging technique illuminates immune status of monkeys with HIV-like virus

July 12, 2018, NIH/National Institute of Allergy and Infectious Diseases
T cell function, relationship to disease, and location in the human body. Credit: NIAID

Findings from an animal study suggest that a non-invasive imaging technique could, with further development, become a useful tool to assess immune system recovery in people receiving treatment for HIV infection. Researchers used single-photon emission computed tomography (SPECT) and a CD4-specific imaging probe to assess immune system changes throughout the bodies of macaques infected with SIV, a simian form of HIV, following initiation and interruption of antiretroviral therapy (ART). They evaluated pools of CD4+ T cells, the main cell type that HIV infects and destroys, in tissues such as lymph nodes, spleen and gut.

Their findings illustrate that CD4+ T-cell levels in the blood—a measure of immune system health in people living with HIV—often fail to fully reflect the situation in tissues. A low blood CD4+ T-cell level indicates an immune system weakened by HIV, and the level generally increases when ART is started and the immune system begins to recover. The new research, led by scientists at the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, delineates the complexity of the immune recovery process at the level of different tissues.

SPECT imaging data from seven monkeys chronically infected with SIV revealed that the timing of reconstitution of the CD4+ T-cell pool in the months following ART initiation varied among animals, and among clusters of within the same animal. Furthermore, reconstitution of CD4+ T-cell pools in the lymph nodes of animals receiving long-term ART appeared suboptimal; they remained smaller than the pools seen in healthy control animals. CD4+ T-cell pools in the spleen appeared similar in the two groups.

The scientists also assessed changes in CD4+ T-cell pools in the gut, which is considered a major target for HIV infection. In contrast to the findings in lymph nodes and spleen, the investigators observed few differences in gut CD4+ T-cell pools between healthy and SIV-infected , challenging the notion that the gut is the major target of SIV infection.

In the future, extension of this imaging technology to humans may aid scientists in evaluating immune reconstitution following standard and experimental HIV treatments, the authors conclude.

Explore further: How intestinal worms hinder tuberculosis vaccination

More information: Michele Di Mascio et al, Total body CD4+ T cell dynamics in treated and untreated SIV infection revealed by in vivo imaging, JCI Insight (2018). DOI: 10.1172/jci.insight.97880

Related Stories

How intestinal worms hinder tuberculosis vaccination

May 17, 2018
New research in mice suggests that chronic infection with intestinal worms indirectly reduces the number of cells in lymph nodes near the skin, inhibiting the immune system's response to the Bacille Calmette-Guerin (BCG) ...

Revving up innate control of viral infection requires a three-cell ignition

July 5, 2018
One of the most important cell types for controlling certain viral infections are natural killer (NK) cells. As part of the innate and rapid immune response, NK-cell recruitment and activation was thought to be a straightforward ...

Worm infection reveals cross-talk in the lymph nodes

August 28, 2017
By studying a worm infection, EPFL scientists have discovered how lymphatic vessels grow within lymph nodes, with major implications for cancer and inflammation.

Regulatory T cells harbor HIV/SIV virus during antiviral drug treatment

October 17, 2017
Scientists at Yerkes National Primate Research Center, Emory University have identified an additional part of the HIV reservoir, immune cells that survive and harbor the virus despite long-term treatment with antiviral drugs.

Understanding immune system interplay to improve organ transplant success

May 31, 2018
A rare opportunity to analyse both blood and tissue samples from human transplant recipients has allowed immunology researchers at the Babraham Institute to pinpoint how an immunosuppressive drug works to prevent the production ...

Recommended for you

Scientists create most accurate tool yet developed to predict asthma in young children

December 13, 2018
Scientists at Cincinnati Children's Hospital Medical Center have created and tested a decision tool that appears to be the most accurate, non-invasive method yet developed to predict asthma in young children.

New genetic study could lead to better treatment of severe asthma

December 12, 2018
The largest-ever genetic study of people with moderate-to-severe asthma has revealed new insights into the underlying causes of the disease which could help improve its diagnosis and treatment.

Researchers discover unique immune cell likely drives chronic inflammation

December 11, 2018
For the first time, researchers have identified that an immune cell subset called gamma delta T cells that may be causing and/or perpetuating the systemic inflammation found in normal aging in the general geriatric population ...

Macrophage cells key to helping heart repair—and potentially regenerate, new study finds

December 11, 2018
Scientists at the Peter Munk Cardiac Centre have identified the type of cell key to helping the heart repair and potentially regenerate following a heart attack.

Study identifies a key cellular mechanism that triggers pneumonia in humans

December 11, 2018
The relationship between influenza and pneumonia has long been observed by health workers. Its genetic and cellular mechanisms have now been investigated in depth by scientists in a study involving volunteers and conducted ...

Immune cells sacrifice themselves to protect us from invading bacteria

December 11, 2018
Immune systems are working overtime as winter approaches. Stomach flu can turn the strongest individual into a bedridden convalescent. Viruses are spreading in kindergartens. This year's flu is approaching in full swing. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.