Pathogen infections are recognized by the immune system, which consists of two types of responses: an innate immune response and an antigen-specific adaptive immune response. The innate response is characterized by being the first line of defense that occurs rapidly in which leukocytes such as neutrophils, monocytes, macrophages, eosinophils, mast cells, dendritic cells, etc., are involved. These cells recognize the pathogen-associated molecular patterns (PAMPs), which have been evolutionarily conserved by the diversity of microorganisms that infect humans. Recognition of these pathogen-associated molecular patterns occurs through pattern recognition receptors such as Toll-like receptors and some other intracellular receptors such as nucleotide oligomerization domain (NOD), with the aim of amplifying the inflammation and activating the adaptive cellular immune response, through the antigenic presentation. In the present chapter, we will review the importance of the main components involved in the innate immune response, such as different cell types, inflammatory response, soluble immune mediators and effector mechanisms exerted by the immune response against bacteria, viruses, fungi, and parasites; all with the purpose of eliminating them and eradicating the infection of the host.
Part of the book: Physiology and Pathology of Immunology
Adipose tissue is composed mainly by adipocytes and stromal-vascular fraction, which are composed by different cell types including macrophages. There are three types of adipose tissue: brown (BrAT), white (WAT), and beige (BeAT). BrAT is less abundant and is implicated in lipid oxidation and energy balance; BeAT has the pathway of adaptive thermogenesis, and WAT is endocrine in nature and lipid storage site and is implicated as an endocrine organ that secretes hormones and different molecules. These molecules are pro-inflammatory and anti-inflammatory factors, including the adipokines leptin, adiponectin, resistin, and visfatin, as well as cytokines and chemokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, leptin, adiponectin, and others, are involved with the development of adipose tissue inflammation and obesity. This pathological condition, together with other factors such as oxidative stress, may develop insulin resistance and the pathogenesis of type 2 diabetes mellitus (T2DM).
Part of the book: Adipose Tissue
The immune response is known as a physiological mechanism to protect the body, providing defense to different systems that compose it and allowing its proper functioning. The ability to keep the organism free from foreign agents depends on the mechanisms of natural resistance or innate immunity, as well as the resistance that can develop over time through adaptive immunity. However, when these defense mechanisms fail, it can trigger injuries and diseases in the tissues, such as hypersensitivity, which is characterized as an excessive and undesirable reaction, produced by the immune system; as well as autoimmunity, which refers to the failure of the mechanisms of immunological tolerance, causing the reaction of the immune system against the body itself.
Part of the book: Immunoregulatory Aspects of Immunotherapy
Currently, it is estimated that more than 11 million humans in the world are infected by helminth parasites of Trichinella species, mainly by Trichinella spiralis (T. spiralis), responsible for causing Trichinellosis disease in both animals and humans. Trichinellosis is a cosmopolitan parasitic zoonotic disease, which has direct relevance to human and animal health, because it presents a constant and important challenge to the host’s immune system, especially through the intestinal tract. Currently, there is an intense investigation of new strategies in pharmacotherapy and immunotherapy against infection by Trichinella spiralis. In this chapter, we will present the most current aspects of biology, epidemiology, immunology, clinicopathology, pharmacotherapy and immunotherapy in Trichinellosis.
Part of the book: Parasites and Parasitic Diseases
Pathogen infections are recognized by the immune system, which consists of two types of responses: an innate immune response that recognizes pathogen-associated molecular patterns (PAMPs) and an antigen-specific adaptive immune response. In both responses, there are several activated cells of the immune system, which play a key role in establishing the environment of cytokines, thus directing their differentiation either suppressing or promoting the immune response. This immune response is crucial against pathogen infections. In this chapter, we will describe the crucial role played by different families of cytokines during activation of the immune system to eliminate infectious pathogens.
Part of the book: Immune Response Activation and Immunomodulation
Inflammation is a physiological response of the innate immune system against several endogenous or exogenous stimuli. Inflammation begins with an acute pattern; however, it can become chronic by activating the adaptive immune response through cellular and noncellular mechanisms. The main etiologic factor of periodontal disease is bacteria which substantially harbor the human oral cavity. The most common periodontal diseases are gingivitis and periodontitis, whose main characteristic is inflammation. The knowledge of how immune mechanisms and inflammatory responses are regulated is fundamental to understanding the pathogenesis of periodontal disease. The purpose of this chapter is to show the current panorama of the immunological mechanisms involved in the pathogenesis of periodontal disease.
Part of the book: Periodontal Disease
Dendritic cells (DC) represent an important link between innate and adaptive immunity, which play an important role during the immune response against pathogens. There are several populations and subpopulations of DC, but mainly two subpopulations are characterized: the classic DC specialized in the processing and presentation of the antigen; and the plasmacytoid DC that have a high phagocytic activity and capacity for the production of cytokines. This chapter aims to present the current aspects related to the most relevant characteristics and functions of DC, as well as their role in host defense against infections by viruses, parasites, bacteria, and fungi.
Part of the book: Cell Interaction