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HIV/AIDS
Published in Patricia G. Melloy, Viruses and Society, 2023
Initially, the amount of HIV viral particles detected in the blood typically peaks a few weeks after infection, and then begins to drop off as the virus is controlled by the immune system at least temporarily, known as the early phase of infection. During the chronic stage of the infection, the amount of virus in the blood stabilizes at some level, known as the viral set point. This set point is an important indicator of the patient’s prospects (Simon and Ho 2003). Tracking the amount of virus in the blood could give some indication of whether the person would begin to move into an AIDS progression period (Walker 2008a). Blood tests indicating less than 200 T-helper cells per microliter of blood would mean that a person’s immune system is in serious trouble and may be entering Stage 3 AIDS (Cruse and Lewis 2009).
The Thoracic Lymphatic System and Lymph Nodes, and the Spread of Tumours within the Lungs, the Tracheobronchial Tree and the Mediastinum.
Published in Fred W Wright, Radiology of the Chest and Related Conditions, 2022
Lymphocytes are the basic cells of the lymphoid system and are of three main types - B, T and Null (i.e. not B or T). B lymphocytes when stimulated by antigens differentiate into plasma-cells which in turn produce antibodies. T lymphocytes are of several types: - (i) T-helper cells which produce cytokines and assist B lymphocytes, macrophages and granulocytes, (ii) T-cytoxic cells which destroy cells infected with viruses and tumour cells, and (iii) T-suppressor cells which turn down an immune response. Null cells destroy cells coated with antibodies. T cells are particularly produced in the thymus. Lymphocytes circulate in the blood, rapidly detect antigens (many are specific to certain antigens) and stimulate the production of more lymphocytes in nodes etc. to cause the immune response.
Autoimmune Disorders across the Lifespan
Published in Michelle Tollefson, Nancy Eriksen, Neha Pathak, Improving Women's Health Across the Lifespan, 2021
The immune system consists of both the innate and adaptive system. A stronger innate and adaptive immune response in women contributes to an increased susceptibility to AIDs. The innate immune system is the body’s first line of defense and is activated immediately upon exposure of the body to a pathogen. The second line of defense, the adaptive immune system, is acquired, antigen specific, and categorized as humoral or cell mediated. Humoral immunity consists mostly of B cells. Cell-mediated immunity consists of T cells. A subset of T cells known as T helper cells are categorized as Th1 or Th2 and are the major producers of cytokines. Pro-inflammatory cytokines are produced by Th1 cells and anti-inflammatory cytokines are produced by Th2 cells.
In Silico and in Vivo Analysis of HIV-1 Rev Regulatory Protein for Evaluation of a Multiepitope-based Vaccine Candidate
Published in Immunological Investigations, 2022
Samaneh H. Shabani, Kimia Kardani, Alireza Milani, Azam Bolhassani
To assess the cytokine induction of candidate epitopes, we used IL4pred (https://webs.iiitd.edu.in/raghava/il4pred/) and IFNepitope (https://webs.iiitd.edu.in/raghava/ifnepitope/) web servers. One of the critical steps in vaccine design is determination of antigenic regions that activate T-helper cells. There are various types of T-helper cells including Th1, Th2, Th17, and each type of T-helper cells generates specific type of cytokines. For instance, IFN-γ was released by Th1 and eliminates intracellular pathogens. Thus, identification of IFN-γ inducing T-helper cells must be done to design an effective subunit vaccine (Dhanda et al. 2013b). The secretion of Interleukin-4 (IL4) is the characteristic of Th2 responses. IL4 has a critical function in antibody isotype switching and triggers the generation of IgE (Dhanda et al. 2013a).
HIV TB coinfection - perspectives from India
Published in Expert Review of Respiratory Medicine, 2021
Bharat Bhushan Rewari, Amitabh Kumar, Partha Pratim Mandal, Anoop Kumar Puri
Infection with HIV elicits both innate and adaptive immunity, including cellular and humoral response. However, HIV persists as a chronic infection due to genomic integration of the virus, cellular latency, and genetic variability, leading to immune escape. Cluster Determinant (CD)8+ lymphocytes have a key role in initial control of viremia but eventually immune system becomes exhausted and dysfunctional [14]. A persistent antigenic stimulation leads to dysfunction of T cells; however, the hallmark of HIV infection is the depletion of CD4 + T helper cells. The CD 4 + T helper cells confer Cell Mediated Immunity (CMI) and primarily provide the defense against TB infection [15]. Consequently, there can be a reactivation of TB, re-infection by exogenous TB bacteria or development of progressive primary disease in HIV infection.
Core-shell nanotherapeutics with leukocyte membrane camouflage for biomedical applications
Published in Journal of Drug Targeting, 2020
T cells are composed of many subsets, including CD4+ T cells (helper T cells), CD8+ T cells (cytotoxic T cells), T-regulatory cells, among others [55]. Adopting the specific T cell subpopulations for medical use might increase the precision of molecule recognition and the efficacy of disease control. Inspired by the specific depletion of CD4+ T helper cells by HIV (human immunodefiiency virus) in AIDS (acquired immunodefiiency syndrome), Zhang and co-authors proposed a novel strategy to neutralise HIV viruses. They successfully derived CD4+ T cell membrane and fabricated T helper cell membrane coated PLGA nanoparticles. These nanoparticles present human CD4 receptor and CCR5/CXCR4 coreceptor with native conformation and act as T cell decoys, thus selectively binding with HIV envelop glycoprotein gp120 to inhibit gp120-induced apoptosis of CD4+ T cells [56]. Similar strategies were investigated by Liu and co-authors to camouflage paclitaxel loaded PLGA nanoparticles with cytotoxic T cell membrane, the local low-dose irradiation was introduced as a chemoattractant to enhance tumour targeted drug delivery, through upregulating the expression of adhesion molecules in tumour vessels for cytotoxic T cell membrane coated nanoparticles binding [57].