Cyclization in the cleavamine series: x-ray analysis of N(a)-acetyl-7-ethyl-5-desethyl-aspidospermidine N(b)-methiodide.
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Alkaloids↗
Biomedical subjects
J Trotter
Publications and source records attributed to J Trotter.
Selection and properties of a mouse L-cell transformant expressing human transferrin receptor.
Transferrin receptors are expressed in large quantities on tissues with high requirements for iron such as maturing erythroid cells and placenta. In addition, they are found in abundance on proliferating cells from other normal tissues as well as on a variety of tumours. Recent genetic analysis has shown that structural genes for the transferrin receptor, probably transferrin itself and for p97, a melanoma-associated antigen that exhibits primary sequence homology with transferrin and that can bind ferric iron, each map in man to chromosome 3 (refs 9-12). On this basis it has been suggested that there may be a region on chromosome 3 containing genes involved in Fe transport and that rearrangements in this region of chromosome 3 may in some circumstances be associated with malignant transformation. Furthermore, it is unresolved whether all cell types express structurally identical transferrin receptors. To study these problems, and as an initial step towards cloning the transferrin receptor gene, we describe here the derivation of mouse L-cell transformants expressing the human transferrin receptor.
Animals↗
Thymocyte subpopulation enriched for progenitors with an unrearranged T-cell receptor beta-chain gene.
The development of T cells within the thymus is not well understood. It is known that thymocytes are derived from a progenitor cell in the bone marrow, the prothymocyte, and that cells in the subcapsular area of the thymus can give rise to progeny in both the cortex and the medulla. However, it is not clear whether all medullary thymocytes are necessarily derived from cortical cells. In particular, it has been difficult to distinguish intrathymic progenitor cells. Recently, however, Lesley et al. have defined a thymocyte subpopulation which can be isolated by treatment of the thymus with cytotoxic anti-Thy-1 antibodies and that seems to be enriched for thymocyte progenitors as measured first by its ability to repopulate transiently the thymus of an irradiated host, and second, by its high content of cells bearing Pgp-1 (refs 10, 11), a cell-surface glycoprotein of relative molecular mass 95,000 that is present on most or all prothymocytes of the bone marrow and on fetal thymocytes, but on only a few per cent of cells in the adult thymus. We show here that the gene encoding the beta-chain of the T-cell receptor for antigen, which is rearranged during T-cell ontogeny, is predominantly in the germline configuration in these cells.
Animals↗
T-cell clones specific for myelin basic protein induce chronic relapsing paralysis and demyelination.
Experimental allergic encephalomyelitis (EAE) serves as a model for autoimmune diseases mediated by T lymphocytes. Following sensitization to rat, mouse or guinea pig myelin basic protein (MBP) in complete Freund's adjuvant, inbred mouse strains PL/J (H-2u), SJL/J (H-2s) and (PL/J X SJL/J)F1((PLSJ)F1) develop EAE. Whereas sensitization to the N-terminal 37 amino-acid peptide of rat or guinea pig MBP [MBP(1-37)] induces EAE in PL/J mice, immunization to the C-terminal peptide (89-169) leads to EAE in SJL/J mice. The immune response to MBP in (PLSJ)F1 mice is not co-dominant; sensitization to the N-terminal peptide induces EAE, while sensitization to the C-terminal peptide does not. We have generated MBP-specific T-cell clones restricted to class II (Ia) antigens of the major histocompatibility complex (MHC) from PL/J and (PLSJ)F1 mice following sensitization to rat MBP. Two such I-Au-restricted T-cell clones that proliferate in response to the encephalitogenic N-terminal MBP peptide and recognize a shared determinant with mouse (self) MBP cause paralysis in 100% of (PLSJ)F1 mice tested. Paralysis is induced even when recipients are injected with as few as 1 X 10(5) cloned T cells. Relapsing paralysis followed in two-thirds of the recipients after recovery from acute paralysis, whereas one-third developed chronic persistent paralysis, a form of EAE not usually seen. Histopathology revealed intense perivascular inflammation, demyelination and remyelination within the central nervous system of paralysed mice. The experimental disease induced with these clones shares important features with human demyelinating diseases such as multiple sclerosis. This is the first demonstration that T-cell clones that respond to a defined self-antigen can induce clinical and histological autoimmune disease.
Animals↗