Stories about: B cells

Gut microbes teach young B cells. The question is, what are they teaching them?

A necktie with drawings of antibodies
B cells learn early on how to make many kinds of antibodies. What role do microbes in the gut play in teaching them to do so?

Your immune system’s B cells can produce antibodies against an amazing number of pathogens—viruses, bacteria, etc.—without ever having encountered them. That’s because, as they develop, your B cells reshuffle their antibody-producing genes into an amazing number of possible combinations—more than 100 million—to produce what’s called your primary pre-immune B cell repertoire.

It’s long been thought that in people and in mice this reshuffling process—called V(D)J recombination, after the B cells’ antibody-coding V, D and J gene segments—takes place in two places: the bone marrow and the spleen. But new research from a team led by Frederick Alt, PhD, and Duane Wesemann, MD, PhD, suggests that there may be one more place B cells go to undergo recombination: the gut. What’s more, that reshuffling in the gut may be influenced by the microbes that live there.

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Immune system to Epstein-Barr virus-fueled cancers: “I’ve got an eye on you”

In the vast majority of us, the Epstein-Barr virus (above) causes mild illness and never bothers us again. However, it can lay dormant in small numbers of B cells for years, waking up if the immune surveillance keeping it in check is broken and fueling lymphomas. (NCI)

Some 90 percent of us are exposed to the Epstein-Barr virus (EBV) at some point in our lives. While the immune system’s T cells rapidly clear most EBV-infected B cells, about one in a million infected cells escapes destruction. Within these cells, the virus enters a latent phase, kept in check by the watchful eye of so-called memory T cells.

This uneasy relationship usually holds steady for the rest of our lives, unless something suppresses the immune system – such as infection with HIV or use of anti-rejection drugs after a transplant – and breaks the surveillance. The virus can then reawaken and drive the development of certain B cell cancers.

How do our T cells keep their watch?

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