scholarly journals NFATc1/αA and Blimp-1 Support the Follicular and Effector Phenotype of Tregs

2022 ◽  
Vol 12 ◽  
Author(s):  
Anika Koenig ◽  
Martin Vaeth ◽  
Yin Xiao ◽  
Cristina M. Chiarolla ◽  
Raghu Erapaneedi ◽  
...  

CD4+CXCR5+Foxp3+ T-follicular regulatory (TFR) cells control the germinal center responses. Like T-follicular helper cells, they express high levels of Nuclear Factor of Activated T-cells c1, predominantly its short isoform NFATc1/αA. Ablation of NFATc1 in Tregs prevents upregulation of CXCR5 and migration of TFR cells into B-cell follicles. By contrast, constitutive active NFATc1/αA defines the surface density of CXCR5, whose level determines how deep a TFR migrates into the GC and how effectively it controls antibody production. As one type of effector Treg, TFR cells express B lymphocyte-induced maturation protein-1 (Blimp-1). Blimp-1 can directly repress Cxcr5 and NFATc1/αA is necessary to overcome this Blimp-1-mediated repression. Interestingly, Blimp-1 even reinforces the recruitment of NFATc1 to Cxcr5 by protein-protein interaction and by those means cooperates with NFATc1 for Cxcr5 transactivation. On the contrary, Blimp-1 is necessary to counterbalance NFATc1/αA and preserve the Treg identity. This is because although NFATc1/αA strengthens the follicular development of Tregs, it bears the inherent risk of causing an ex-Treg phenotype.

2018 ◽  
Vol 115 (34) ◽  
pp. 8621-8626 ◽  
Author(s):  
Lan He ◽  
Wangpeng Gu ◽  
Meng Wang ◽  
Xiaoyan Chang ◽  
Xiaoyu Sun ◽  
...  

T-follicular helper (TFH) cells are a subset of CD4+ helper T cells that help germinal center (GC) B-cell differentiation and high-affinity antibody production during germinal center reactions. Whether important extracellular molecules control TFH differentiation is not fully understood. Here, we demonstrate that a secreted protein extracellular matrix protein 1 (ECM1) is critical for TFH differentiation and antibody response. A lack of ECM1 inhibited TFH cell development and impaired GC B-cell reactions and antigen-specific antibody production in an antigen-immunized mouse model. ECM1 was induced by IL-6 and IL-21 in TFH cells, promoting TFH differentiation by down-regulating the level of STAT5 phosphorylation and up-regulating Bcl6 expression. Furthermore, injection of recombinant ECM1 protein into mice infected with PR8 influenza virus promoted protective immune responses effectively, by enhancing TFH differentiation and neutralizing antibody production. Collectively, our data identify ECM1 as a soluble protein to promote TFH cell differentiation and antibody production.


2021 ◽  
Author(s):  
C. N. Jondle ◽  
K. E. Johnson ◽  
W. P. Mboko ◽  
V. L. Tarakanova

Gammaherpesviruses are ubiquitous pathogens that establish life-long infection and are associated with B cell lymphomas. To establish chronic infection, these viruses usurp B cell differentiation and drive a robust germinal center response to expand the latent viral reservoir and gain access to memory B cells. Germinal center B cells, while important for the establishment of latent infection, are also thought to be the target of viral transformation. The host and viral factors that impact the gammaherpesvirus-driven germinal center response are not clearly defined. We showed that global expression of the antiviral and tumor-suppressor interferon regulatory factor 1 (IRF-1) selectively attenuates the murine gammaherpesvirus 68 (MHV68)-driven germinal center response and restricts expansion of the latent viral reservoir. In this study we found that T cell intrinsic IRF-1 expression recapitulates some aspects of antiviral state imposed by IRF-1 during chronic MHV68 infection, including attenuation of the germinal center response and viral latency in the spleen. We also discovered that global and T cell-intrinsic IRF-1 deficiency leads to unhindered rise of IL-17A-expressing and follicular helper T cell populations, two CD4 + T cell subsets that support chronic MHV68 infection. Thus, this study unveils a novel aspect of antiviral activity of IRF-1 by demonstrating IRF-1-mediated suppression of specific CD4 + T cell subsets that support chronic gammaherpesvirus infection. Importance Gammaherpesviruses infect over 95% of the adult population, last the lifetime of the host, and are associated with multiple cancers. These viruses usurp the germinal center response to establish lifelong infection in memory B cells. This manipulation of B cell differentiation by the virus is thought to contribute to lymphomagenesis, though exactly how the virus precipitates malignant transformation in vivo is unclear. IRF-1, a host transcription factor and a known tumor suppressor, restricts the MHV68-driven germinal center response in a B cell-extrinsic manner. We found that T cell intrinsic IRF-1 expression attenuates the MHV68-driven germinal center response by restricting the CD4 + T follicular helper population. Further, our study identified IRF-1 as a novel negative regulator of IL-17-driven immune responses, highlighting the multifaceted role of IRF-1 in gammaherpesvirus infection.


2020 ◽  
Vol 217 (9) ◽  
Author(s):  
Xin Li ◽  
Liying Gong ◽  
Alexandre P. Meli ◽  
Danielle Karo-Atar ◽  
Weili Sun ◽  
...  

Antigen uptake and presentation by naive and germinal center (GC) B cells are different, with the former expressing even low-affinity BCRs efficiently capture and present sufficient antigen to T cells, whereas the latter do so more efficiently after acquiring high-affinity BCRs. We show here that antigen uptake and processing by naive but not GC B cells depend on Cbl and Cbl-b (Cbls), which consequently control naive B and cognate T follicular helper (Tfh) cell interaction and initiation of the GC reaction. Cbls mediate CD79A and CD79B ubiquitination, which is required for BCR-mediated antigen endocytosis and postendocytic sorting to lysosomes, respectively. Blockade of CD79A or CD79B ubiquitination or Cbls ligase activity is sufficient to impede BCR-mediated antigen processing and GC development. Thus, Cbls act at the entry checkpoint of the GC reaction by promoting naive B cell antigen presentation. This regulation may facilitate recruitment of naive B cells with a low-affinity BCR into GCs to initiate the process of affinity maturation.


Immunity ◽  
2011 ◽  
Vol 34 (6) ◽  
pp. 947-960 ◽  
Author(s):  
Steven M. Kerfoot ◽  
Gur Yaari ◽  
Jaymin R. Patel ◽  
Kody L. Johnson ◽  
David G. Gonzalez ◽  
...  

Blood ◽  
2015 ◽  
Vol 125 (15) ◽  
pp. 2381-2385 ◽  
Author(s):  
Patricia Amé-Thomas ◽  
Sylvia Hoeller ◽  
Catherine Artchounin ◽  
Jan Misiak ◽  
Mounia Sabrina Braza ◽  
...  

Key Points CD10 identifies a unique subset of fully functional germinal center TFH that are activated and amplified within the FL cell niche. FL CD10pos TFH specifically display an IL-4hiIFN-γlo cytokine profile and encompass the malignant B-cell-supportive TFH subset.


2015 ◽  
Vol 194 (12) ◽  
pp. 5604-5608 ◽  
Author(s):  
Jessica A. Yang ◽  
Noah J. Tubo ◽  
Micah D. Gearhart ◽  
Vivian J. Bardwell ◽  
Marc K. Jenkins

Sign in / Sign up

Export Citation Format

Share Document