Biomedical subjects

S A Ellis

Publications and source records attributed to S A Ellis.

42 records · Page 3Linked to original sources

PubMed1988

Ankylosing spondylitis without B27: no evidence for gene conversion.

Isoelectric focusing gel electrophoresis was used to look for variant HLA molecules in five patients with HLA-B27 negative ankylosing spondylitis (AS). The isoelectric points of the HLA-A and B antigens from these patients and HLA paired controls were identical. This implies that the HLA-A and B antigens from the patients with AS and the controls are similar. Gene conversion of a nucleotide sequence from a B27 positive gene is thus unlikely to be the explanation for the existence of AS in patients who are HLA-B27 negative by alloantisera typing.

Female↗

PubMed1986

Evidence for a novel HLA antigen found on human extravillous trophoblast and a choriocarcinoma cell line.

We describe the characterization of a novel HLA Class I molecule, which we have isolated from chorionic cytotrophoblast cell membranes, and from a trophoblast-derived choriocarcinoma cell line, BeWo; classical HLA Class I antigens are not expressed on these cells. This antigen is an electrophoretically non-polymorphic glycoprotein of approximately 40,000 molecular weight, which is found in association with beta 2 microglobulin, and which is detected by monoclonal antibodies recognizing monomorphic determinants of HLA Class I. Elucidation of the nature and origin of this molecule may provide valuable information regarding the immune barrier that exists between mother and fetus.

Antigens, Neoplasm↗

PubMed1985

Characterization of the HLA-A2.2 subtype: T cell evidence for further heterogeneity.

Five blood donors were identified whose HLA-A2 is different from the common HLA-A2. Their A2 molecule (A2.2) had a more basic isoelectric point than normal A2 (A2.1). Cytotoxic T lymphocytes (CTL) restricted by HLA-A2.1, specific for influenza A and Epstein-Barr viruses, failed to lyse virus-infected target cells with HLA-A2.2. Identical patterns were obtained with both viruses. CTL from four of the A2.2-positive donors recognized target cells prepared from others in the group that shared only the HLA-A2.2 antigen. The A2.2 antigen from one donor seemed to be different in that target cells were not recognized by CTL from donors with the normal A2.1 nor with basic A2.2. There seems, therefore, to be heterogeneity within the HLA-A2.2 subtype.

Cytotoxicity, Immunologic↗

PubMed1985

An HLA class I specific monoclonal antibody that fails to bind to all HLA-A antigens.

A monoclonal antibody, MHM.5, specific for HLA class I antigens, bound to lymphocytes of all donors tested and was thought to bind to a monomorphic determinant. When the antibody was used to precipitate 35S methionine labeled HLA class I molecules from lymphoid cells, which were then isoelectric focused, it was found that the HLA-A1,A2 and A3 antigens were not precipitated. Similarly, MHM.5, which is IgG1, failed to block complement mediated lysis by alloantisera specific for HLA-A1, 2 and 3, and most other HLA-A antigens. HLA-Aw24, A25, and A32, and all other HLA-B and C typing reactions tested were blocked. Thus the antibody binds to an epitope that is lacking on most A antigens, but present on Aw24, A25, A32 and all B and C locus antigens. Comparison of the published amino acid sequences of HLA-A2, A3, Aw24, A28, Cw3, B7, and B40 suggests some possible sites for this epitope.

Antibodies, Monoclonal↗

PubMed1982

Recognition of HLA-B27 and related antigen by a monoclonal antibody.

A monoclonal antibody that binds specifically to HLA-B27, B7, and B22 is described. Binding to B27 appeared to be slightly stronger than to B7 and stronger than to B22 in an indirect binding assay, but no difference in B7 and B27 binding could be detected by Scatchard analysis. No distinction could be made between B27 on cells from normal and from ankylosing spondylitis patients in any assay system. The antibody, which was not cytotoxic, blocked complement-dependent cytolysis mediated by human HLA typing sera specific for B7 and B27. Competitive binding studies with other monoclonal antibodies showed that ME1 could block the binding of antibodies that recognized different antigenic sites on HLA. ME1 did not bind to Klebsiella pneumoniae. This reagent will be useful in further analysis of the relationship between B27 and ankylosing spondylitis.

Absorption↗

PubMed1980

Size heterogeneity of rat pituitary prolactin.

The occurrence of multiple forms of rat prolactin with different molecular weights (size heterogeneity) was studied with anterior pituitary extracts, purified rat prolactin and 125I-labelled rat prolactin. In each case, three main forms of the hormone were detected by gel filtration on Sephadex G-100: a major one (80--90%) corresponding to monomeric prolactin (mol.wt. 22000--25000), a peak (8--20%) that could be a dimer (mol.wt. 45000--50000) and a small quantity (1--5%) of a component of much greater molecular weight. On freezing and thawing of 125I-labelled rat prolactin, there was little interconversion of monomer and 'dimer' peaks, but both were converted substantially to very high-molecular-weight material. All three peaks of 125I-labelled rat prolactin could be precipitated by anti-(rat prolactin) serum and all three gave similar patterns of radioactive peptides after digestion with chymotrypsin followed by high-voltage paper electrophoresis. On sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the monomer peak of 125I-labelled prolactin migrated as a single component of mol.wt. 22000, the very high-molecular-weight peak largely dissociated to a component running in the same position as the monomer, and the 'dimer' peak migrated partly as a component of mol.wt. 45000 and partly as a component migrating with monomeric prolactin. No treatment was found that could dissociate the 'dimer' peak completely to monomeric prolactin.

Animals↗