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Biomedical subjects

H M Grey

Publications and source records attributed to H M Grey.

194 records · Page 11Linked to original sources
PubMed1967

Carboxy-terminal amino acids of gamma-A and gamma-M heavy chains.

The carboxy-terminal amino acids of alpha-and micro-chains from human immunoglobulins and alpha-chains from mouse immunoglobulins have been determined by carboxypeptidase digestion and hydrazinolysis. The data suggest the following carboxy-terminal sequences: human micro: Ala-Gly-Thr-Cys-TyrCOOH; human alpha: Thr-Cys-TyrCOOH; murine alpha: (Ileu, Cys)-TyrCOOH.

Amino Acid Sequence↗
PubMed1966

Recombination of heavy and light chains of human gamma-a-myeloma proteins: formation of hybrid molecules and configurational specificity.

The present studies demonstrate that the conditions necessary for reductive cleavage, isolation, and recombination of L and H polypeptide chains of human gammaA-myeloma globulins parallel those required for similar manipulation of the component chains of gammaG-globulin. Specificity of recombination was shown for chains derived from the same protein. In contrast, no intradass preferential recombination was demonstrable. Hybrid molecules, formed by reassociation of noncovalent bonds, could be synthesized from isolated chains of two immunoglobulin classes resulting in the formation of molecules of the type gammaA-H-gammaG-L and gammaG-H-gammaA-L. Several sera containing both gammaA- and gammaG-"monoclonal" peaks were studied, one of which demonstrated the L chains associated with both peaks to be identical both by electrophoretic mobility in acid-urea gel and antigenic analysis. The possibility is considered that this case represents a naturally occurring analogue of the artificially produced hybrid molecules described in this study. Configurational antigenic specificity of gammaA-myeloma proteins, imposed by the presence of kappa L chains in native and appropriately recombined molecules, provides a further indication of the importance of noncovalent bonds in the establishment of the quaternary structure of these proteins.

Immunodiffusion↗
PubMed1966

Low-molecular-weight proteins related to Bence Jones proteins in multiple myeloma.

Urinary proteins distinct from Bence Jones proteins, but sharing antigenic determinants, were found in the urine of a number of patients with multiple myeloma. These components were smaller in size and antigenically deficient compared with Bence Jones proteins. They were best detected with antiserums to the homologous Bence Jones proteins and, in some cases, were related to the variable portion of the Bence Jones protein molecule.

Bence Jones Protein↗
PubMed1965

Specificity of recombination of H and L chains from human gamma-G-myeloma proteins.

Dissociated H and L chains of human gammaG-myeloma proteins were recombined by removal of conditions interrupting non-covalent interactions. In the process of recombination 7S molecules were formed. It was demonstrated that the H chains from individual gammaG-myeloma proteins recombine with their own L chains but also with L chains derived from other myeloma proteins. In some instances, however, the L chains from other myeloma proteins did not recombine as avidly with the H chains as the autologous L chains. The specificity of the non-covalent interactions of H and L chains was particularly well brought out by competitive recombination experiments where an individual H chain had a choice of recombining with its own L chain or with the L chain obtained from another myeloma protein. In this manner a spectrum of affinities between individual H chains and several L chains was demonstrated. In the vast majority of recombinations there was a clearcut preference for recombination to take place between the H and L chains derived from the same protein. It is postulated that this specificity is related to differences in the primary structure, which cause differences in configuration of these homogeneous H and L chains and that these configurations then dictate on thermodynamic grounds the pairing of H chains with particular L chains.

Humans↗
PubMedDate not supplied

Antigen degradation by macrophages as an obligatory step in the presentation of antigen to T lymphocytes.

Evidence is presented which supports the hypothesis of protein degradation taking place in macrophages as a part of the presentation of antigen to T lymphocytes. It is postulated that the ability of T cells to recognize both native and denatured forms of the same protein is dependent upon degradation of both forms of the protein to yield the same peptides and thus results in the stimulation of identical subsets of T cells. The occasional observation of a lack of cross-reactivity could result if the native antigen is particularly resistant to the denaturing conditions found within macrophages.

Antibody Formation↗
PubMedDate not supplied

Structural characteristics of an antigen required for its interaction with Ia and recognition by T cells.

A detailed analysis of the residues within an immunogenic peptide that endow it with the capacity to interact with Ia and to be recognized by T cells is presented. Ia interacts with only a few of the peptide residues and overall exhibits a very broad specificity. Some residues appear to interact both with Ia and with T cells, leading to a model in which a peptide antigen is 'sandwiched' between Ia and the T-cell receptor.

Amino Acid Sequence↗
PubMedDate not supplied

Antigen analogues as antagonists of the T cell receptor.

Complexes of antigen analogues and major histocompatibility complexes have been demonstrated to function as effective antagonists of the T cell receptor (TCR). It was observed that modification of any of the major T cell contact residues can create powerful TCR antagonists. Increasing similarity of antagonist to antigen structure resulted in increased capacity to act as a TCR antagonist up to a point beyond which the analogues themselves showed antigenicity. These data strongly suggested that peptide: TCR interaction with a certain low affinity may still be sufficient for engagement of the receptor but not for signalling, thus resulting in antagonism. It was found that the presentation of antagonistic peptides alone did not induce the formation of stable conjugates between antigen presenting cells and T cells, but rather that presentation of antigen was required to induce the initial interaction of APC with T cells in cell:cell conjugates. This antigen-dependent conjugate formation was not affected by the antagonist, while very early intracellular biochemical events such as PI turnover and CA2+ flux were inhibited.

Antigen-Presenting Cells↗