T-Cell Subsets: Role of Cell Surface Structures.

Certain well-conserved genes in fluorescent Pseudomonas spp. are involved in pathogenic interactions between the bacteria and evolutionarily diverse hosts including plants, insects and vertebrate animals. One such gene, dsbA, encodes a periplasmic disulfide-bond-forming enzyme implicated in the biogenesis of exported proteins and cell surface structures. This study focused on the role of dsbA in Pseudomonas fluorescens Q8r1-96, a biological control strain that produces the antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) and is known for its exceptional ability to colonize the roots of wheat and pea. The deduced DsbA protein from Q8r1-96 is similar to other predicted thiol : disulfide interchange proteins and contains a conserved DsbA catalytic site, a pattern associated with the thioredoxin family active site, and a signal peptide and cleavage site. A dsbA mutant of Q8r1-96 exhibited decreased motility and fluorescence, and altered colony morphology; however, it produced more 2,4-DAPG and total phloroglucinol-related compounds and was more inhibitory in vitro to the fungal root pathogen Gaeumannomyces graminis var. tritici than was the parental strain. When introduced separately into a natural soil, Q8r1-96 and the dsbA mutant did not differ in their ability to colonize the rhizosphere of wheat in greenhouse experiments lasting 12 weeks. However, when the two strains were co-inoculated, the parental strain consistently out-competed the dsbA mutant. It was concluded that dsbA does not contribute to the exceptional rhizosphere competence of Q8r1-96, although the dsbA mutation reduces competitiveness when the mutant competes with the parental strain in the same niche in the rhizosphere. The results also suggest that exoenzymes and multimeric cell surface structures are unlikely to have a critical role in root colonization by this strain.

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The role of unconventional T cells in COVID-19

Irish Journal of Medical Science (1971 -) ◽

10.1007/s11845-021-02653-9 ◽

2021 ◽

Author(s):

Kristen Orumaa ◽

Margaret R. Dunne

Keyword(s):

Immune Response ◽

T Cells ◽

T Cell ◽

Treatment Strategies ◽

Γδ T Cells ◽

Protective Role ◽

T Cell Subsets ◽

Viral Immunity ◽

Mait Cells

AbstractCOVID-19 is a respiratory disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It was first documented in late 2019, but within months, a worldwide pandemic was declared due to the easily transmissible nature of the virus. Research to date on the immune response to SARS-CoV-2 has focused largely on conventional B and T lymphocytes. This review examines the emerging role of unconventional T cell subsets, including γδ T cells, invariant natural killer T (iNKT) cells and mucosal associated invariant T (MAIT) cells in human SARS-CoV-2 infection.Some of these T cell subsets have been shown to play protective roles in anti-viral immunity by suppressing viral replication and opsonising virions of SARS-CoV. Here, we explore whether unconventional T cells play a protective role in SARS-CoV-2 infection as well. Unconventional T cells are already under investigation as cell-based immunotherapies for cancer. We discuss the potential use of these cells as therapeutic agents in the COVID-19 setting. Due to the rapidly evolving situation presented by COVID-19, there is an urgent need to understand the pathogenesis of this disease and the mechanisms underlying its immune response. Through this, we may be able to better help those with severe cases and lower the mortality rate by devising more effective vaccines and novel treatment strategies.

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Association of a tetraspanin CD9 with CD5 on the T cell surface: role of particular transmembrane domains in the association

International Immunology ◽

10.1093/intimm/11.12.2043 ◽

1999 ◽

Vol 11 (12) ◽

pp. 2043-2052 ◽

Cited By ~ 29

Author(s):

Kazuhito Toyo-oka ◽

Yumi Yashiro-Ohtani ◽

Cheung-Seog Park ◽

Xu-Guang Tai ◽

Kensuke Miyake ◽

...

Keyword(s):

T Cell ◽

Cell Surface ◽

Transmembrane Domains

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The Role of Cytokines in the Modulation of Cell Surface Antigens of Human Melanoma

The International Journal of Biological Markers ◽

10.1177/172460089300800303 ◽

1993 ◽

Vol 8 (3) ◽

pp. 151-154 ◽

Cited By ~ 2

Author(s):

A. Anichini ◽

R. Mortarini ◽

G. Parmiani

Keyword(s):

Cell Surface ◽

Surface Antigens ◽

Surface Structures ◽

Biological Behavior ◽

Cell Surface Antigens ◽

Membrane Expression ◽

Neoplastic Cells ◽

Antigenic Modulation ◽

Human Malignant Melanoma ◽

Cell Surface Structures

A number of different cytokines, including IL-1α. and ß, IL-2, IL-3, IL-4, IL-6, IL-7, IL-8, IFN-α, -ß and γ, TNF-α -ß, and TGF-ß1, can modulate the expression of distinct cell surface antigens of normal and neoplastic cells. Both induction/increase of expression and reduction of expression can be achieved depending on the antigen and on the cytokine. Antigens subjected to the modulating activity of cytokines include distinct families of cell surface structures such as the molecules coded by the major histocompatibility complex (MHC), the superfamily of adhesion receptors that regulate cell-cell and cell-matrix interaction, receptors for cytokines and growth factors and tumor-associated antigens. The modulating activity of cytokines is a consequence of their influence on gene expression, protein synthesis, membrane expression and shedding of antigens from the cell surface. The changes of phenotype due to the action of cytokines can influence the signalling pathways dependent on the expression and function of cell surf ace structures. Therefore, the antigen modulating activity of cytokines can thoroughly affect the biological behavior of normal and neoplastic cells. As described here, most of the modulating effects of cytokines on different cell surface structures and the functional consequences of antigenic modulation can be verified in human malignant melanoma cells.

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