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Author

Christopher A. Smith

Other affiliations: Keele University
Bio: Christopher A. Smith is an academic researcher from University of Birmingham. The author has contributed to research in topics: Plasmid & Operon. The author has an hindex of 24, co-authored 34 publications receiving 6825 citations. Previous affiliations of Christopher A. Smith include Keele University.

Papers
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Journal ArticleDOI
12 Jan 1989-Nature
TL;DR: It is shown that engaging the CD3/TCR complex of immature mouse thymocytes with anti-CD3 antibodies produces DNA degradation and cell death through the endogenous pathway of apoptosis.
Abstract: The receptors found on most T lymphocytes bind to antigen presented on major histocompatibility complex proteins and consist of dimers of alpha- and beta-polypeptides associated with the invariant CD3 complex. A fully competent immune system requires a diverse array of T-cell antigen receptors (TCRs) with different specificities. This diversity is generated by rearrangement of TCR alpha- and beta-chain gene segments within the thymus where the receptors are first expressed. Any cells carrying self-reactive receptors must be eliminated, suppressed or inactivated so that destructive autoimmunity is avoided. Recently, compelling evidence has shown that one process involved in producing such self-tolerance is clonal deletion of autoreactive cells within the thymus by an as-yet-undefined mechanism. Here we show that engaging the CD3/TCR complex of immature mouse thymocytes with anti-CD3 antibodies produces DNA degradation and cell death through the endogenous pathway of apoptosis. Activation of this process in immature T cells by the binding of the TCR to self-antigens may therefore be the mechanism which produces clonal deletion and consequently self-tolerance.

1,163 citations

Journal ArticleDOI
01 Dec 1989-Nature
TL;DR: It is found that, on culture, centrocytes isolated from human tonsil kill themselves within a few hours by apoptosis, not a feature of other tonsillar B cells.
Abstract: The high affinity of antibodies produced during responses to T-cell-dependent antigens is associated with somatic mutation in the variable region of the immunoglobulin. Indirect evidence indicates that: (1) this arises by a process of hypermutation, acting selectively on rearranged immunoglobulin variable-region genes, which is activated in centroblasts within germinal centres; and (2) centrocytes, the progeny of centroblasts, undergo selection on the basis of their ability to receive a positive signal from antigen. We have now performed experiments analysing this selection process, and found that, on culture, centrocytes isolated from human tonsil kill themselves within a few hours by apoptosis. This is not a feature of other tonsillar B cells. Centrocytes can be prevented from entering apoptosis if they are activated both through their receptors for antigen and a surface glycoprotein recognized by CD40 antibodies.

1,091 citations

Journal ArticleDOI
04 Jan 1990-Nature
TL;DR: It is shown that the death of haemopoietic precursor cells on withdrawal of the relevant CSF is due to active cell death5, or apoptosis, indicating that CSFs promote cell survival by suppression of the process of apoptosis.
Abstract: The survival, differentiation, proliferation and development of haemopoietic precursor cells and the functional activity of mature blood cells are all influenced by colony stimulating factors (CSFs). As haemopoietic cells rapidly die in the absence of appropriate CSF, the promotion of cell survival mediated by CSFs, or growth factors, is fundamental to all the other effects exerted by these factors. This enhancement of cell survival is distinct from the stimulation of proliferation. Here we show that the death of haemopoietic precursor cells on withdrawal of the relevant CSF. is due to active cell death, or apoptosis, indicating that CSFs promote cell survival by suppression of the process of apoptosis. The existence of a positive control mechanism regulating precursor cell survival has important implications both for the regulation of normal haemopoiesis and for tumorigenesis.

956 citations

Journal ArticleDOI
10 Sep 1993-Cell
TL;DR: It is now widely accepted that apoptosis is a genedirected process and can be seen, alongside more familiar gene-directed processes like differentiation, as part of the repertoire available to the cell to respond to external and internal stimuli.

940 citations

Journal ArticleDOI
TL;DR: Although apoptosis is now accepted as a critical element in the repertoire of potential cellular responses, the picture of the intra-cellular processes involved is probably still incomplete, not just in its details, but also in the basic outline of the process as a whole.
Abstract: The field of apoptosis is unusual in several respects. Firstly, its general importance has been widely recognised only in the past few years and its surprising significance is still being evaluated in a number of areas of biology. Secondly, although apoptosis is now accepted as a critical element in the repertoire of potential cellular responses, the picture of the intra-cellular processes involved is probably still incomplete, not just in its details, but also in the basic outline of the process as a whole. It is therefore a very interesting and active area at present and is likely to progress rapidly in the next two or three years.

683 citations


Cited by
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Journal ArticleDOI
TL;DR: Attention is focussed on the ROS/RNS-linked pathogenesis of cancer, cardiovascular disease, atherosclerosis, hypertension, ischemia/reperfusion injury, diabetes mellitus, neurodegenerative diseases, rheumatoid arthritis, and ageing.

12,240 citations

Journal ArticleDOI
10 Mar 1995-Science
TL;DR: In multicellular organisms, homeostasis is maintained through a balance between cell proliferation and cell death, and recent evidence suggests that alterations in cell survival contribute to the pathogenesis of a number of human diseases.
Abstract: In multicellular organisms, homeostasis is maintained through a balance between cell proliferation and cell death. Although much is known about the control of cell proliferation, less is known about the control of cell death. Physiologic cell death occurs primarily through an evolutionarily conserved form of cell suicide termed apoptosis. The decision of a cell to undergo apoptosis can be influenced by a wide variety of regulatory stimuli. Recent evidence suggests that alterations in cell survival contribute to the pathogenesis of a number of human diseases, including cancer, viral infections, autoimmune diseases, neurodegenerative disorders, and AIDS (acquired immunodeficiency syndrome). Treatments designed to specifically alter the apoptotic threshold may have the potential to change the natural progression of some of these diseases.

6,462 citations

Journal ArticleDOI
TL;DR: A flow cytometric method for measuring the percentage of apoptotic nuclei after propidium iodide staining in hypotonic buffer is developed and shown an excellent correlation with the results obtained with both electrophoretic and colorimetric methods.

4,660 citations

Journal ArticleDOI
22 Nov 1990-Nature
TL;DR: It is demonstrated that Bcl-2 is an integral inner mitochondrial membrane protein of relative molecular mass 25,000 (25k) being localized to mitochondria and interfering with programmed cell death independent of promoting cell division.
Abstract: The t(14; 18) chromosomal translocation of human follicular B-cell lymphoma juxtaposes the bcl-2 gene with the immunoglobulin heavy chain locus. The bcl-2 immunoglobulin fusion gene is markedly deregulated resulting in inappropriately elevated levels of bcl-2 RNA and protein. Transgenic mice bearing a bcl-2 immunoglobulin minigene demonstrate a polyclonal expansion of resting yet responsive IgM-IgD B cells which display prolonged cell survival but no increase in cell cycling. Moreover, deregulated bcl-2 extends the survival of certain haematopoietic cell lines following growth-factor deprivation. By using immunolocalization studies we now demonstrate that Bcl-2 is an integral inner mitochondrial membrane protein of relative molecular mass 25,000 (25k). Overexpression of Bcl-2 blocks the apoptotic death of a pro-B-lymphocyte cell line. Thus, Bcl-2 is unique among proto-oncogenes, being localized to mitochondria and interfering with programmed cell death independent of promoting cell division.

3,773 citations

Journal ArticleDOI
03 Apr 1992-Cell
TL;DR: It is demonstrated that deregulated c-myc expression induces apoptosis in cells growth arrested by a variety of means and at various points in the cell cycle.

3,047 citations