#immune memory

[bpod-bpod]

Seeing and Remembering

In the eye, immunity means a delicate balance between fighting pathogens and avoiding any excess inflammation, that could impede vision. This is especially critical in the outermost layer, the transparent cornea, which must remain clear but is also the front line for infections. Unlike most tissues, the central cornea was thought to be devoid of resident memory T cells, immune cells that recognise previously-encountered pathogens and can quickly respond to infection. Yet new research has overturned that view: sophisticated microscopy techniques revealed that, in mice, infecting the cornea (pictured) with herpes simplex virus (in cyan) leads to recruitment of T cells (in green), which then give rise to more persistent memory T cells. Evidence of similar-looking cells moving around in the corneas of healthy human volunteers suggests our eyes may also have some form of immune memory, with implications for the treatment of chronic dry eye and other eye diseases.

Written by Emmanuelle Briolat

Image from work by Joon Keit Loi and Yannick O. Alexandre, and colleagues

Department of Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia

Image copyright held by the original authors

Research published in Cell Reports, May 2022

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[gorskon]

Tetyana Obukhanych swings at the measles immune amnesia studies—and whiffs!

Tetyana Obukhanych has a PhD in immunology but has somehow become antivaccine. This week, she tried to refute two recent studies on immune amnesia induced by measles virus infection. Let's just say that it did not go well.

The other day, I wrote about a couple of fascinating new papers that provide yet more evidence that measles is not a “benign childhood disease.” Basically, the papers presented yet more confirmation that the measles virus can attack the immune system, resulting in “immune amnesia,” in which the immune system “forgets” how to make antibodies against antigens it’s previously encountered before. If…

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[touba]

Original antigenic sin, also known as the Hoskins effect, refers to the propensity of the body's immune system to preferentially utilize immunological memory based on a previous infection when a second slightly different version, of that foreign entity (e.g. a virus or bacterium) is encountered. This leaves the immune system "trapped" by the first response it has made to each antigen, and unable to mount potentially more effective responses during subsequent infections. The phenomenon of original antigenic sin has been described in relation to influenza virus, dengue fever, human immunodeficiency virus (HIV), and to several other viruses.

This phenomenon was first described in 1960 by Thomas Francis, Jr. in the article "On the Doctrine of Original Antigenic Sin". It is named by analogy to the theological concept of original sin. According to Thomas Francis who originally described the idea and cited by Richard Krause:

"The antibody of childhood is largely a response to dominant antigen of the virus causing the first type A influenza infection of the lifetime. [...] The imprint established by the original virus infection governs the antibody response thereafter. This we have called the Doctrine of the Original Antigenic Sin."

(via)