Immunology

Type I interferons (IFN-α/β) and the more recently identified type III IFNs (IFN-λ) function as the first line of defense against virus infection and regulate the development of both innate and adaptive immune responses. Type III IFNs were originally identified as a novel ligand-receptor system acting in parallel with type I IFNs, but subsequent studies have provided increasing evidence for distinct roles for each IFN family. In addition to their compartmentalized antiviral actions, these two systems appear to have multiple levels of cross-regulation and act coordinately to achieve effective antimicrobial protection with minimal collateral damage to the host.

Publication date: 4 May 2017
Source:Cell, Volume 169, Issue 4
Author(s): Davide F. Robbiani, Leonia Bozzacco, Jennifer R. Keeffe, Ricardo Khouri, Priscilla C. Olsen, Anna Gazumyan, Dennis Schaefer-Babajew, Santiago Avila-Rios, Lilian Nogueira, Roshni Patel, Stephanie A. Azzopardi, Lion F.K. Uhl, Mohsan Saeed, Edgar E. Sevilla-Reyes, Marianna Agudelo, Kai-Hui Yao, Jovana Golijanin, Harry B. Gristick, Yu E. Lee, Arlene Hurley, Marina Caskey, Joy Pai, Thiago Oliveira, Elsio A. Wunder, Gielson Sacramento, Nivison Nery, Cibele Orge, Federico Costa, Mitermayer G. Reis, Neena M. Thomas, Thomas Eisenreich, Daniel M. Weinberger, Antonio R.P. de Almeida, Anthony P. West, Charles M. Rice, Pamela J. Bjorkman, Gustavo Reyes-Teran, Albert I. Ko, Margaret R. MacDonald, Michel C. Nussenzweig
Antibodies to Zika virus (ZIKV) can be protective. To examine the antibody response in individuals who develop high titers of anti-ZIKV antibodies, we screened cohorts in Brazil and Mexico for ZIKV envelope domain III (ZEDIII) binding and neutralization. We find that serologic reactivity to dengue 1 virus (DENV1) EDIII before ZIKV exposure is associated with increased ZIKV neutralizing titers after exposure. Antibody cloning shows that donors with high ZIKV neutralizing antibody titers have expanded clones of memory B cells that express the same immunoglobulin VH3-23/VK1-5 genes. These recurring antibodies cross-react with DENV1, but not other flaviviruses, neutralize both DENV1 and ZIKV, and protect mice against ZIKV challenge. Structural analyses reveal the mechanism of recognition of the ZEDIII lateral ridge by VH3-23/VK1-5 antibodies. Serologic testing shows that antibodies to this region correlate with serum neutralizing activity to ZIKV. Thus, high neutralizing responses to ZIKV are associated with pre-existing reactivity to DENV1 in humans.
Graphical abstract Teaser Individuals with high neutralizing antibody response against Zika virus have expanded clones of B cells that express the same heavy and light immunoglobulin genes and that are cross-reactive against dengue 1 virus.

Researchers in dermatology at Lund University in Sweden believe they have cracked the mystery of why we are able to quickly prevent an infection from

Selection and maturation of B cells into plasma cells producing high-affinity antibodies occur in germinal centers (GC). GCs form transiently in secondary lymphoid organs upon antigen challenge, and the GC reaction is a highly regulated process. TGF-β is a potent negative regulator, but the influence of other family members including bone morphogenetic proteins (BMPs) is less known. Studies of human peripheral blood B lymphocytes showed that BMP-6 suppressed plasmablast differentiation, whereas BMP-7 induced apoptosis. Here, we show that human naïve and GC B cells had a strikingly different receptor expression pattern. GC B cells expressed high levels of BMP type I receptor but low levels of type II receptors, whereas naïve B cells had the opposite pattern. Furthermore, GC B cells had elevated levels of downstream signaling components SMAD1 and SMAD5, but reduced levels of the inhibitory SMAD7. Functional assays of GC B cells revealed that BMP-7 suppressed the viability-promoting effect of CD40L and IL-21, but had no effect on CD40L- and IL-21-induced differentiation into plasmablasts. BMP-7-induced apoptosis was counteracted by a selective TGF-β type I receptor (ALK4/5/7) inhibitor, but not by a selective BMP receptor type I inhibitor. Furthermore, overexpression of truncated ALK5 in a B-cell line counteracted BMP-7-induced apoptosis, whereas overexpression of truncated ALK4 had no effect. BMP-7 mRNA and protein was readily detected in tonsillar B cells, indicating a physiological relevance of the study. Altogether, we identified BMP-7 as a negative regulator of GC B-cell survival. The effect was counteracted by truncated ALK5, suggesting greater complexity in regulating BMP-7 signaling than previously believed.

Binding of T cell receptors (TCR) to peptide-loaded major histocompatibility complexes (p/MHC) leads to T-cell activation.

Immunological memory – the ability of the body to ‘remember’ and fight previously encountered pathogens – forms the basis of vaccination, which is one of the most important discoveries in the history of medicine. However, despite the enormous success of vaccination, we still do not fully understand how the body maintains long-term immunological memory, and this gap in our knowledge is hindering attempts to develop ‘next-generation vaccines’ and efforts to deploy immune cells called T cells against cancer. The immune system contains many different types of cells. Some of these cells can recognize pathogens without ever having encountered them. However,

End-stage differentiation of antigen-specific T-cells may precede loss of immune responses against e.g. viral infections after allogeneic stem cell transplantation (SCT). Antigen-specific CD8+ T-cells detected by HLA/peptide multimers largely comprise CD45RA-/CCR7- effector memory (TEM) and CD45RA+/CCR7- TEMRA subsets. A majority of terminally differentiated T-cells is considered to be part of the heterogeneous TEMRA subset. The senescence marker CD57 has been functionally described in memory T-cells mainly composed of central memory (TCM) and TEM cells. However, its role specifically in TEMRA cells remained undefined. Here, we investigated the relevance of CD57 to separate human CD8+ TEMRA cells into functionally distinct subsets. CD57- CD8+ TEMRA cells isolated from healthy donors had considerably longer telomeres and showed significantly more BrdU uptake and IFN-γ release upon stimulation compared to the CD57+ counterpart. Cytomegalovirus (CMV) specific T-cells isolated from patients after allogeneic SCT were purified into CD57+ and CD57- TEMRA subsets. CMV specific CD57- TEMRA cells had longer telomeres and a considerably higher CMV peptide sensitivity in BrdU uptake and IFN-γ release assays compared to CD57+ TEMRA cells. In contrast, CD57+ and CD57- TEMRA cells showed comparable peptide specific cytotoxicity. Finally, CD57- CD8+ TEMRA cells partially changed phenotypically into TEM cells and gained CD57 expression, while CD57+ CD8+ TEMRA cells hardly changed phenotypically and showed considerable cell death after in vitro stimulation. To the best of our knowledge, these data show for the first time that CD57 separates CD8+ TEMRA cells into a terminally differentiated CD57+ population and a so far functionally undescribed “young” CD57- TEMRA subset with high proliferative capacity and differentiation plasticity.

Cellular and Molecular Immunology aims to report the dynamic progress being made in China and abroad in immunological research, and welcomes high-quality Research Articles, Reviews and Brief Reports across a broad range of topics including, but not limited to, clinical immunology, comparative immunology, immunobiology, immunogenetics, immunological techniques, immunopathology, immunopharmacology, infection immunology, neuroimmunology, transplantation immunology, tumor immunology, and veterinary immunology.

Recent advances in single-cell RNA-sequencing (scRNA-seq) technology increase the understanding of immune differentiation and activation processes, as well as