The Innate and Adaptive Immune Systems
Bruce Alberts, Alexander Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter in Molecular Biology of the Cell, 2017
This chapter focuses on vertebrate immune responses and the features that distinguish them from other kinds of cell responses. It begins with innate immune defenses and then discusses the highly specialized properties of the adaptive immune system. Like antibody responses, T-cell-mediated immune responses are exquisitely antigen-specific, and they are at least as important as antibodies in defending vertebrates against infection. Indeed, most adaptive immune responses, including most antibody responses, require helper T cells for their initiation. Most importantly, unlike B cells, T cells can help eliminate pathogens that have entered the interior of host cells, where they are invisible to B cells and antibodies. The chapter concerns how T cells accomplish this feat. Some of the cell-surface proteins discussed in the chapter that belong to the immunoglobulin (Ig) superfamily. There are three main classes of T cells—cytotoxic T cells, helper T cells, and regulatory T cells.
Immune Responses
André Marette, Éliane Picard-Deland, Melissa Anne Fernandez in Yogurt: Roles in Nutrition and Impacts on Health, 2017
The immune system protects the body against environmental pathogens and is divided into two subclasses: the innate (nonspecific) and the adaptive immune system. The adaptive or acquired immune system is characterized by specific responses toward each antigen and by enhanced responses after repeated antigen encounters (immune memory). Lymphocytes (T and B cells) are the main effector cells of the adaptive immune system. B cells are responsible for antibody production (humoral response), whereas helper T cells and T regulatory cells either directly destroy pathogens (cytotoxic T cells, i.e., CD8 + T lymphocytes) or control the function of other cell types (helper T cells, i.e., CD4 + T lymphocytes). Helper T cells can produce different cytokines, such as interferon-gamma (IFN-γ), tumor necrosis factor (TNF-α), and interleukins IL-4 and IL-5 ( Meydani and Ha 2000 ).
CANCERS IN AIDS PATIENTS
James Bishop in Cancer Facts, 1999
INTRODUCTION Cancer is an important association of chronic immunodeficiency states. In human immunodeficiency virus (HIV) infection, the virus causes a slow relentless deterioration in T-cell immune function with an average of 10 years from primary infection until acquired immunodeficiency syndrome (AIDS), develops. As helper T cells (CD4) decline the immune system fails leading to the well-recognised complications of AIDS occurring, such as opportunistic infections and cancer.
T cell epitope engineering: an avian H7N9 influenza vaccine strategy for pandemic preparedness and response
Published in Human Vaccines & Immunotherapeutics, 2018
Leonard Moise, Bethany M. Biron, Christine M. Boyle, Nese Kurt Yilmaz, Hyesun Jang, Celia Schiffer, Ted M. Ross, William D. Martin, Anne S. De Groot
The delayed availability of vaccine during the 2009 H1N1 influenza pandemic created a sense of urgency to better prepare for the next influenza pandemic. Advancements in manufacturing technology, speed and capacity have been achieved but vaccine effectiveness remains a significant challenge. Here, we describe a novel vaccine design strategy called immune engineering in the context of H7N9 influenza vaccine development. The approach combines immunoinformatic and structure modeling methods to promote protective antibody responses against H7N9 hemagglutinin (HA) by engineering whole antigens to carry seasonal influenza HA memory CD4+ T cell epitopes – without perturbing native antigen structure – by galvanizing HA-specific memory helper T cells that support sustained antibody development against the native target HA. The premise for this vaccine concept rests on (i) the significance of CD4+ T cell memory to influenza immunity, (ii) the essential role CD4+ T cells play in development of neutralizing antibodies, (iii) linked specificity of HA-derived CD4+ T cell epitopes to antibody responses, (iv) the structural plasticity of HA and (v) an illustration of improved antibody response to a prototype engineered recombinant H7-HA vaccine. Immune engineering can be applied to development of vaccines against pandemic concerns, including avian influenza, as well as other difficult targets.
Dysbiosis of gut microbiota induced the disorder of helper T cells in influenza virus-infected mice
Published in Human Vaccines & Immunotherapeutics, 2015
Bin Yu, Cong-qi Dai, Jia Chen, Li Deng, Xian-lin Wu, Sha Wu, Chang-lin Zhao, Zhen-you Jiang, Xiao-yin Chen
It is widely understood that commensal microbiota contributes to the maintenance of intestinal homeostasis through dynamic interactions with a body's immunity. And the immune regulation is important for the influenza vaccine's effectiveness after body injection, however, the mechanism between commensal microbiota and vaccine's effectiveness remains unknown. The impact that individual bacteria species have on the balance of the systemic immune system beyond the local intestinal mucosal tissues also remains less clear, and the related mechanism is still unknown. In this study, through the administration of various antibiotics, we examined the balance of helper T cell subsets in mice after inoculating them with the influenza virus and then, attempted to imitate the clinical practice in which patients are always prescribed with an antibiotic treatment in flu season. The data indicates that the mice in each group present differential immune responses in terms of the makeup of helper T cell subsets, although the Th17 cell activity seems to not be involved in the systemic immune modulation in the mice that are susceptible to the intervention of antibiotic. Th1, Th2, and anti-inflammatory regulatory T cells have been implicated in the contribution to the systemic immune response influenced by the antibiotic-induced dysbiosis. Thus we believe that the normal intestinal flora could maintain the immune balance and inhibit the inflammatory responses, which may be useful for clinical application to take intestinal flora into consideration when influenza vaccination was used.
The role of interleukin-9 in lymphoma
Published in Leukemia & Lymphoma, 2013
Although much progress has been made in the treatment of lymphomas, the unclear molecular etiology limits its further development. Interleukin-9 (IL-9) was initially described as a growth factor secreted by activated helper T cells type 2 (Th2). Various observations have demonstrated its diverse actions in immune and inflammatory responses. In recent years, a resurgence of interest in IL-9 has been spurred by the expanded identification of its cellular sources and biological targets. Also, the determination of its growth-proliferative and anti-apoptotic activities on multiple transformed cells implies a potential role of this cytokine in tumorigenesis. In this article we review the biologic properties and signal transduction pathways of IL-9, and furthermore discuss its possible role in lymphomagenesis as well as its impact on non-malignant infiltrating cells which are characteristic of the tumor microenvironment.
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