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Biomedical subjects

A Feinstein

Publications and source records attributed to A Feinstein.

At least 127 records · Page 7Linked to original sources
PubMed1981

Fibronectin and C4-binding protein are selectively bound by aggregated amyloid P component.

Serum amyloid P component (SAP) is a normal plasma protein, closely related to C-reactive protein, which is deposited together with amyloid fibrils in all forms of amyloidosis. It is also a normal constituent of human tissues, where it is found in vascular basement membranes and in association with the peripheral microfibrillar mantle of elastic fibres throughout the body. Very similar, highly conserved, homologous proteins are present in the sera of all vertebrates in which they have been sought, and in all cases these proteins display calcium-dependent binding affinity for agarose. The physiological function or pathogenetic significance of this reactivity are not known but we report here for the first time that under appropriate conditions human SAP can also bind certain serum glycoproteins. SAP, which had been aggregated either by direct conjugation to CNBr-activated Sepharose beads, or by complexing with anti-SAP antibodies immobilized on such beads, selectively took up fibronectin and C4-binding protein from whole normal human serum. The reaction was calcium dependent and the two ligands were bound independently of each other or of other serum constituents. Experiments with isolated fibronectin and SAP complexed by anti-SAP-Sepharose indicated that close association of pairs of SAP molecules was required for fibronectin to be bound and that each SAP dimer was capable of taking up a single molecule of fibronectin. There was no evidence that SAP in its native state in the serum was complexed with either fibronectin or C4-binding protein. The present findings significantly extend knowledge of the properties of SAP and open the way to characterisation of its physiological ligand(s) and thence to elucidation of its function.

Amyloid↗
PubMed1980

Structure of hydrated immunoglobulins and antigen-antibody complexes. Electron microscopy of spray-freeze-etched specimens.

The structure of spray-frozen IgG and IgM, either free in solution or specifically bound to bacterial flagella is compared after freeze-etching with the corresponding preparations negatively stained. The freeze-etched IgG is readily detected; most of the hydrated particles appear approximately spherical with an average diameter of about 12 nm. About 20% are triangular with sides of about 13-14 nm. Antibodies attached to flagella are clearly seen on the top as well as the exposed edges. The technique can thus be used for antigen localization on freeze-etched macromolecules and also on the surface of larger structures. The dimensions and shape of freeze-etched bound IgM confirm the earlier interpretations of the structure of this antibody based on negative staining.

Antigen-Antibody Complex↗
PubMed1980

Herpes zoster in a husband and wife.

The wife of a 75-year-old man with zoster began to suffer from this disease some 24 days after is appeared in her husband. Although zoster is generally regarded to be an endogenously noncommunicable disease, the case reported herein suggests that the infection was exogenously communicated. The literature pointing up that zoster may possibly be acquired exogenously, particularly in immunosuppressed patients, is extensively reviewed.

Aged↗
PubMed1979

Detection of protein A-like substances on haemolytic streptococci prior to use in mixed reverse passive antiglobulin haemagglutination (MRPAH).

Before mixed reverse passive antiglobulin haemagglutination tests (MRPAH) can be used to measure the class of bacterial antibodies, the bacteria have to be shown to be free of Protein A or Protein A-like substances on their surfaces. Two basic procedures have been examined: haemagglutination of red cells coated with immunoglobulin by the bacteria, and the MRPAH reaction itself to reveal absorption of purified gamma Fc by the bacterial suspension. The use of a purified gamma Fc component has proved successful in providing a sensitive test for the detection of Protein A-like substances on the surface of bacterial. In addition to both the Cowan and Wood strains of Staph, aureus, strains of haemolytic streptococci of groups A, C and G had Protein A-like substances on their surfaces. In contrast, strains of group B and group D, as well as Strep. milleri, had no detectable Protein A-like activity.

Absorption↗
PubMed1978

Mouse intracellular immunoglobulin M. Structure and identification of a free thiol group.

Monomeric intracellular mouse immunoglobulin M (hereafter designated IgMs) was purified in milligram quantities from the plasma cells of mouse plasmacytoma MOPC 104E after lysis either in the presence or in the absence of iodoacetate. Peptide ;mapping' analysis of the IgMs after partial reduction and carboxy[(14)C]methylation to label the interchain disulphide bridges showed that the heavy-light bridge and the interheavy bridge present in the Cmu2 region were already formed at lysis. The cysteine residues in the C-terminal region of the heavy chains, which in pentameric IgM form an intersubunit bridge, had free thiol groups at lysis that were reversibly oxidized during isolation in the absence of iodoacetate, probably forming an intrasubunit inter-heavy-chain disulphide bridge. Isoelectric-focusing studies complemented the above findings, showing that all the intracellular IgMs carried free thiol groups that could be carboxymethylated at lysis, and that in non-alkylated preparations these had reversibly oxidized. On the basis of sodium dodecyl sulphate/polyacrylamide-slab-gel electrophoresis intracellular mu-chains had a consistently lower apparent molecular weight than did secreted mu-chains, and the estimated difference could be accounted for by the known difference in carbohydrate content. We present evidence that in a position homologous to that of a complex oligosaccharide in the Cmu2 region of secreted human mu-chains there is a simple oligosaccharide in intracellular mouse mu-chains that becomes complex on secretion. On the basis of the above findings, we present a model for the mouse intracellular IgM subunit and suggest a mechanism for its assembly into secreted IgM pentamers.

Animals↗
PubMed1978

The class of antibodies sensitizing bacteria measured by mixed reverse passive antiglobulin haemagglutination (MRPAH).

A test is described which is capable of differentiating and measuring by titration the individual classes of antibody reacting with a bacterial suspension. The serum or fluid under test is incubated with the bacteria which are then very well washed and added to indicator red cells linked with specific antiglobulin reagents. Sensitization of the bacteria by a particular class of antibody is shown by haemagglutination (passive) of the appropriate red cells. Agglutination of the bacteria themselves does not preclude an analysis. The reaction, which has been developed on a brucella system, has been designated Mixed Reverse Passive Antiglobulin Haemagglutination (or MRPAH for short).

Antibodies, Anti-Idiotypic↗
PubMed1976

The specificity of the Fc receptor on murine lymphocytes for immunoglobulins of the IgG and IgM classes.

It is shown that the Fc receptor for IgG on lymph node cells recognizes IgG molecules of mouse IgG1, IgG2a and IgG2b subclasses. The presence of an intact CH3 domain is required to bind IgG to the Fc receptors. While monomeric IgG molecules are shown to bind to Fc receptors, heat aggregated IgG was found to bind more efficiently. The various forms of IgM molecules investigated show only weak or no binding in comparison. The significance of these results is discussed with relevance to the possible biological function of the Fc receptors on lymphocytes.

Animals↗
PubMed1976

Restriction in the function of single helper T cells.

T cells involved in specific and nonspecific co-operation belong to a long-lived population. However, under conditions of limiting dilution of T cells it is not a common event to detect both types of co-operative event in a single microculture well. Likewise, as far as specific co-operation is concerned, the simultaneous expression of both direct and indirect PFC responses in a single microculture well is also unusual. Estimates obtained of the number of PFC generated by one T cell in specific co-operation correspond well to those generated by a single B cell; and it would seem that under conditions of the microculture system there is a marked restriction in the number of B cells that a single T cell may interact with in the short term. This restriction seems to be of a one T-cell to one B-cell relationship.

Animals↗