China 
Africa 
Explore chapters and articles related to this topic
The Inducible Defense System: The Induction and Development of the Inducible Defence
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Michael A. Hickey, Diane Wallace Taylor
Antigen processing is a key step in initiation of an inducible immune response. Many bacteria and larger particles are processed and presented by macrophages, whereas viruses invade and are presented by dendritic cells. B cells are most efficient in presenting soluble molecules, including many toxins. Thus, different APC participate in the response to different diseases-causing agents.
Role of Epigenetics in Immunity and Immune Response to Vaccination
Published in Mesut Karahan, Synthetic Peptide Vaccine Models, 2021
The second type of adaptive immunity is cell-mediated immunity. Cell-mediated immunity functions via T cells which are released into circulation following their maturation in the thymus. T cells are categorized as CD4+ cells and CD8+ cells according to the type of T cell receptor (TCR) they express. The helper T cells express CD4 receptors while cytotoxic T cells express CD8 TCR (Margolick, Markham, and Scott 2006). There are two types of helper T cells, Th1 and Th2. Th1 cells are involved in cell-mediated immunity and Th2 cells are involved in antibody-mediated immunity (O’Garra and Arai 2000). In contrast to B cells, T cells require antigen processing by antigen-presenting cells for antigen recognition. Following activation and clonal expansion, memory T cells are produced to induce a rapid immune response for subsequent infections (Pennock et al. 2013). Following their formation, memory T cells can provide immunity for approximately ten years (Hammarlund et al. 2003).
Modulating Cytolytic Responses to Infectious Pathogens
Published in Thomas F. Kresina, Immune Modulating Agents, 2020
Rebecca Pogue Caley, Jeffrey A. Frelinger
Once the peptides are generated in the cytosol, they are transported into the lumen of the endoplasmic reticulum (ER), where they are bound by the class I heavy chains (Figure 1). The major mechanism in the antigen presentation pathway for peptides to be transported is through the transporter complex. The transporter associated with antigen processing (TAP) consists of two subunits, TAP-1 and TAP-2. Cells lines which lack functional TAP molecules show a marked decrease in their cell surface levels of class I [12,15]. Some human leukocyte antigen A2 (HLA-A2) class I complexes which reach the cell surface in the mutant cell line T2 have bound signal sequence derived peptides [16,17]. While the signal sequence pathway provides some of the peptides bound to class I, the majority of peptides entering the antigen presentation pathway enter via the TAP pathway. Transfection of the TAP genes into the TAP-deficient cell lines restores antigen presentation and cell surface MHC levels [18–20]. The subunits of TAP-1 and TAP-2 are 76 and 70 kDa, respectively, and are noncovalently associated. They are thought to function as a dimer, although it is unclear whether high-order multimers occur. The TAP molecules belong to a family of transport proteins which contain an adenosine triphosphate-(ATP)-binding cassette [21]. The TAP-dependent peptide transport is ATP-dependent [22].
The interdependence of machine learning and LC-MS approaches for an unbiased understanding of the cellular immunopeptidome
Published in Expert Review of Proteomics, 2022
Morten Nielsen, Nicola Ternette, Carolina Barra
The early methods for prediction of HLA antigen presentation were focused on predicting the HLA peptide binding event and were trained mainly on HLA peptide binding data derived from in-vitro binding affinity measurements (reviewed in [7]). The cost of generating such data is high, and it is further apparent that in-vitro binding data fails to incorporate important information related to antigen processing and the HLA peptide binding event (such as the stability of the formed pHLA complex, the effect of chaperones shaping the peptide repertoire, and the length distribution of peptides available for binding to HLA molecules). Compared to this, MS immunopeptidome data constitutes an appealing alternative since this data is generated ex-vivo and hence incorporates signatures of all the steps involved in HLA antigen processing and presentation.
Recent strategies driving oral biologic administration
Published in Expert Review of Vaccines, 2021
Badriyah Shadid Alotaibi, Manal Buabeid, Nihal Abdalla Ibrahim, Zelal Jaber Kharaba, Munazza Ijaz, Ghulam Murtaza
Antigen entrance to GIT leads to the migration of mucosal lymphocytes via the lymphatic system. After it, activation of immune cells and their amassing in the effector sites (including lamina propria, epithelial surface, salivary glands) occurs [23,54,55]. Before processing antigens into peptides for their interaction with naïve T cells, antigen internalization occurs under the effect of dendritic cells at the mucosal inductor area. Antigen processing occurs through one of the two pathways. A small number of dendritic cells undergo drainage through the lymphatic system into the mesenteric lymph nodes, followed by the priming of naïve CD4+ T cells. These cells play a role in immune response initiation by activating antigen-specific B cells into IgA+ B cells in the surrounding environment. These activated cells reach the effector sites via the circulatory system. Otherwise, dendritic cell-mediated priming of local naïve CD4+ cells occurs in the Peyer’s patches, followed by activation of antigen-specific B cells into IgA+ B cells. Finally, the transfer of these cells from Peyer’s patches to the effector sites takes place.
Towards customized cancer vaccines: a promising filed in personalized cancer medicine
Published in Expert Review of Vaccines, 2021
Xiaoling Xu, Zichao Zhou, Hui Li, Yun Fan
There are various of the strengths of neoantigen vaccines. First, the neoantigen vaccine contains many neoantigens of different tumors, using the natural ability of the immune system to detect and attack the target antigen, reducing the occurrence of drug resistance. Secondly, neoantigen vaccines are customized for each patient, using antigens produced by the patient’s unique mutations in cancer, and are only present on cancer cells. Targeted tumor vaccines can generate an immune response that only attacks cancer cells, bypassing natural immune tolerance process. Finally, ‘off-target’ effects are rarely seen, with only mild side effects. However, individualized tumor vaccines are designed based on the analysis of individual somatic cell mutations through artificial intelligence software. Complicated preparation procedures and biometric analysis usually takes 2–3 months and the cost is relatively high. Besides, there are several barriers to the successful application of neoantigen-based vaccines. First, it remains difficult to precisely predict which mutated proteins are digested into short peptides by the proteasome, transported into the endoplasmic reticulum by antigen processing transporters, and loaded onto newly synthesized MHCs for recognition by CD8 + T-cells. Second, a rapid assay is needed to validate the predicted neoantigens. Third, rapid manufacturing and timely delivery of neoantigen vaccines remain problematic, as ≥3 months are often required from the initial mutation analysis to clinical vaccine administration. Finally, the optimal clinical setting remains unclear for neoantigen vaccines.