Host Defense II: Acquired Immunity
Constantin A. Bona, Francisco A. Bonilla in Textbook of Immunology, 2019
In cutaneous fungal infections, nonspecific cellular mechanisms predominate initially. While the infection is confined to the stratum corneum, there is exuberant inflammation and activation of neutrophils. When infection reaches the deeper dermal tissues, and the inflammation becomes chronic, mononuclear cells predominate. Fungi adhere to phagocytic cells by a variety of surface molecules. Some adhere directly to structures such as mannose/fucose binding proteins. Histoplasma interacts with the β2 family of integrins (CD11a,b,c/CD18). Many fungi are opsonized with antibodies, or with C3b and/or iC3b produced mainly via the alternative pathway. Phagocytosis of hyphal forms is difficult because of their size, but they may be killed by extracellular mechanisms (release of granule contents). The ability of a phagocytic cell to kill a fungus depends on the type of cell, its tissue of origin (i.e., cell subtype), the species of fungus and its stage of growth (Table 11–II). The oxidative mechanisms of microbial destruction are important for killing of fungi, the myeloperoxidase system, in particular (Chapter 10). Other granule contents are also active, including defensins which have activity against Candida and Cryptococcus.
Interaction of Immune and Connective Tissue Cells
Brian J. Nickoloff in Dermal Immune System, 2019
Several of the lymphocyte adhesion molecules are known as the leukocyte integrins. These molecules are members of a superfamily of adhesion receptors called integrins, each member of which is a heterodimer composed of an α and β subunit. Currently, the integrins are classified according to their beta subunits, i.e., β1, β2, β3, etc. The leukocyte integrins are members of the β2 subfamily comprised of three molecules (LFA-1, MAC-1, and pl50,95) which share a common 95-kDa beta subunit (CD 18) with specific alpha subunits (CD11a, CD11b, and CD11c). The importance of the leukocyte integrins was demonstrated by the discovery of a clinical syndrome called leukocyte adhesion deficiency or LAD that is characterized by a deficiency in the production of the common beta chain, leading to diminished or absent expression of all three β2 integrins. LAD can result in life-threatening infections, aberrant wound healing, and abnormal cell adhesion-dependent functions.
Cellular Trafficking
Martin Berry, Ann Logan in CNS Injuries: Cellular Responses and Pharmacological Strategies, 2019
This family is often referred to as the leucocyte integrins. There are three main groups: CDlla/CD18 is present on virtually all leucocytes, whereas CD11b/CD18 and CD11c/CD18 are mainly confined to phagocytic cells (see Table 6.1). Anti-CD11a antibodies prevent the increased adhesion of leucocytes to cytokine-treated endothelium, and in experimental models of non-CNS inflammation, antibodies against CD11a, CD11b, or CD18 impede the entry of leucocyte infiltrates.33–35 Regulation of integrin expression and binding efficiency is linked to haemopoietic maturation36 and to the state of cell activation. Associated with the transition from naive to memory T cells is an increase in CD11a expression, and it is the memory T cells that preferentially migrate to inflammatory lesions.37,38
TGF-β enhances the cytotoxic activity of Vδ2 T cells
Published in OncoImmunology, 2019
Christian Peters, Annika Meyer, Léonce Kouakanou, Julia Feder, Tim Schricker, Marcus Lettau, Ottmar Janssen, Daniela Wesch, Dieter Kabelitz
A major issue of immunotherapy by adoptive transfer of T cells is how to bring the effector cells into proximity of the targeted tumor cells. The recruitment of lymphocytes into tissues is orchestrated by chemo-attractants and adhesion molecules. LFA-1 (Integrin αL/β2; CD11a/CD18) is the best-characterized molecule of the integrin family and is essential for lymphocyte homing to lymphoid and non-lymphoid tissues as well as for the formation and maintenance of the immunological and cytolytic synapse.9 The integrin αE (CD103)/β7, which interacts with the epithelial cell marker E-cadherin, is known to be important for the retention of lymphocytes within epithelial tissues,10 but is only expressed on about 2% of the peripheral blood mononuclear cells (PBMC) of healthy individuals.11 Moreover, αE (CD103)/β7 activity is important for the acquisition of a dendritic phenotype and the motility of intraepithelial T cells.12
Microparticles and cardiovascular diseases
Published in Annals of Medicine, 2019
Christos Voukalis, Eduard Shantsila, Gregory Y. H. Lip
Chemo-attraction of leukocytes to the inflamed endothelial segment is essential for the progression of atherosclerosis [225]. Microparticles from different cellular origins may trigger production of pro-inflammatory cytokines from the endothelium, such as IL-6 and IL-8, which attract and activate leukocytes [91,226]. Another suggested mechanism which contributes to the progression of the atheroma is linked to microparticles-induced expression of adhesion molecules on the endothelial cells. An example is platelet-derived microparticles mediated upregulation of intercellular adhesion molecule-1 on the endothelial cell membrane [91,227]. Plaque microparticles isolated from endarterectomy specimens could transfer ICAM-1 to endothelium [228]. Also microparticles induce integrin expression on the surface of the leukocytes, such as CD11a and CD11b, which interact with intercellular adhesion molecule-1[91]. Chemokines delivered from microparticles to inflamed or atherosclerotic endothelium promote further leukocyte recruitment. Mause et al. described a platelet-derived microparticle-associated delivery of the chemokine regulated on activation, normal T cell expressed and secreted (RANTES) to human microvascular endothelial cells which promotes monocyte adhesion [83].
PIMS-TS immunophenotype: description and comparison with healthy children, Kawasaki disease and severe viral and bacterial infections
Published in Infectious Diseases, 2022
Alberto García-Salido, Inés Leoz-Gordillo, Anthony González Brabin, María Ángeles García-Teresa, Amelia Martínez-de-Azagra-Garde, María Isabel Iglesias-Bouzas, Marta Cabrero-Hernández, Gema De Lama Caro-Patón, José Luis Unzueta-Roch, Ana Castillo-Robleda, Manuel Ramirez-Orellana, Montserrat Nieto-Moro
We also examined the percentage of CD11a and CD11b positive cells. We observed that both proteins were higher in neutrophils and monocytes than in viral or bacterial infections (Figure 1). Also, they were higher than KD but without significant differences. Related to CD11a, the MFI was also higher in neutrophils of PIMS-TS cases. In adults, the inflammation-based on SARS-CoV-2 showed a predominant presence of macrophages and neutrophils in the affected territory. In PIMS-TS, this increased CD11a expression could be a sign of trafficking. Adding to the previously commented, these findings are congruent with an inflammatory process and the trend of these cells to leave the bloodstream [10]. This adds interesting about the utility of anti-inflammatory drugs as a cornerstone in managing these children [8,12–14].
Related Knowledge Centers
- Cluster of Differentiation
- Efalizumab
- Immunosuppressive Drug
- Integrin
- Gene
- Integrin Beta 2
- Lymphocyte Function-Associated Antigen 1
- Protein–Protein Interaction
- Integrin Alpha X
- Leukocyte Adhesion Deficiency
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