Unsung heroes of antibody production

August 3, 2012
Figure 1: IL-4-secreting Tfh cells (green) reside alongside the B cells of the germinal center (red), and enable them to produce a full spectrum of antibody subtypes. © 2012 Masato Kubo, RIKEN Research Center for Allergy and Immunology

B cells are the body’s antibody factories, standing by to churn out molecules that selectively target foreign threats as a component of the humoral immune response. However, this process also requires T cells to secrete a protein known as interleukin-4 (IL-4), which promotes a mechanism called ‘class switching’ that enables production of functionally specialized antibody subtypes.

It remains unclear exactly which T cells generate the IL-4 signal. Although many scientists favor the Th2 subclass of helper T cells, there are strong arguments against this model as well. “This subset of cells cannot get into the follicles where these B cells are located,” explains Masato Kubo of the RIKEN Research Center for Allergy and Immunology, Yokohama. “Nevertheless, most textbooks say that Th2 cells control the antibody response.”

Kubo and colleagues have now provided strong evidence that a recently discovered class of follicular T (Tfh) cells generates the IL-4 signal that kicks B cells into high gear1. In a previous study, his group identified several stretches of DNA within the gene encoding IL-4 that might regulate its activity2. One candidate sequence, CNS2, had little effect on Th2 production of IL-4, but mice lacking this genomic region nevertheless showed severe defects in class-switching. “We started thinking other T cell subsets might be responsible for IL-4-mediated humoral immune responses,” he says.

By placing a fluorescent gene under the control of CNS2, the researchers showed that this regulatory region is specifically active in Tfh cells. As their name suggests, Tfh cells reside within follicles, in close proximity to the germinal centers where B cells mature. They also actively secrete IL-4 (Fig. 1), albeit by an apparently distinct mechanism from Th2 cells. Kubo’s team found that mutant mice lacking CNS2 can produce mature Tfh cells, but these cells expressed greatly reduced levels of IL-4. By comparison, Th2 cells were only minimally affected. Nevertheless, these genetically modified mice showed striking deficits in their production of several antibody subclasses, including immunoglobulin E (IgE) and G1 (IgG1).

These findings proved surprising at multiple levels. “IL-4 is a critical cytokine for controlling IgG1 and IgE antibody responses, but its expression in Th2 and Tfh cells is independently regulated by distinct elements,” says Kubo. “Furthermore, Tfh and not Th2 cells are the T cell subset responsible for Th2-type humoral immune responses.” He and his colleagues are working to identify the factors that act on CNS2, which could ultimately offer useful drug targets for controlling autoimmune disease by restraining .

Explore further: Transcription factor regulates protein that dampens immune responses

More information: 1. Harada, Y., Tanaka, S., Motomura, Y., Harada, Y., Ohno, S., Ohno, S., Yanagi, Y., Inoue, H. & Kubo, M. The 3’ enhancer CNS2 is a critical regulator of interleukin-4-mediated humoral immunity in follicular helper T cells. Immunity 36, 188–200 (2012).

2. Tanaka, S., Motomura, Y., Suzuki, Y., Yagi, R., Inoue, H., Miyatake, S. & Kubo, M. The enhancer HS2 critically regulates GATA-3-mediated Il4 transcription in TH2 cells. Nature Immunology 12, 77–85 (2011).

Related Stories

Transcription factor regulates protein that dampens immune responses

June 17, 2011
Interleukin-10 (IL-10) is an anti-inflammatory cytokine protein that reduces immune responses and staves off autoimmune disease. Now, a research team led by Masato Kubo at the RIKEN Research Center for Allergy and Immunology, ...

Rewiring DNA circuitry could help treat asthma

July 5, 2012
(Medical Xpress) -- Reprogramming asthma-promoting immune cells in mice diminishes airway damage and inflammation, and could potentially lead to new treatments for people with asthma, researchers have found.

Recommended for you

Australian researchers in peanut allergy breakthrough

August 17, 2017
Australian researchers have reported a major breakthrough in the relief of deadly peanut allergy with the discovery of a long-lasting treatment they say offers hope that a cure will soon be possible.

Genetic variants found to play key role in human immune system

August 16, 2017
It is widely recognized that people respond differently to infections. This can partially be explained by genetics, shows a new study published today in Nature Communications by an international collaboration of researchers ...

Study identifies a new way to prevent a deadly fungal infection spreading to the brain

August 16, 2017
Research led by the University of Birmingham has discovered a way to stop a deadly fungus from 'hijacking' the body's immune system and spreading to the brain.

Biophysics explains how immune cells kill bacteria

August 16, 2017
(Tokyo, August 16) A new data analysis technique, moving subtrajectory analysis, designed by researchers at Tokyo Institute of Technology, defines the dynamics and kinetics of key molecules in the immune response to an infection. ...

How a nutrient, glutamine, can control gene programs in cells

August 15, 2017
The 200 different types of cells in the body all start with the same DNA genome. To differentiate into families of bone cells, muscle cells, blood cells, neurons and the rest, differing gene programs have to be turned on ...

Scientists identify gene that controls immune response to chronic viral infections

August 15, 2017
For nearly 20 years, Tatyana Golovkina, PhD, a microbiologist, geneticist and immunologist at the University of Chicago, has been working on a particularly thorny problem: Why are some people and animals able to fend off ...


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.