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C R Mackay

Publications and source records attributed to C R Mackay.

96 records · Page 6Linked to original sources
PubMed1985

Sheep lymphocyte antigens (OLA). I. Major histocompatibility complex class I molecules.

Three monoclonal antibodies, SBU.I 41-17, 41-19 and 41-28, have been produced which recognize sheep Class I major histocompatibility complex antigens (OLA). All three antibodies are able to precipitate a heavy chain of 44,000 MW and a smaller beta 2-microglobulin of 12,000 MW from 125I-surface labelled lymphocytes. The antibodies have been used to localize OLA Class I antigens in lymphoid and non-lymphoid tissues using indirect immunoperoxidase histological staining and cytofluorograph analyses. Evidence suggests that the three antibodies are directed against monomorphic determinants but that they recognize different epitopes.

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PubMed1985

The sheep analogue of leucocyte common antigen (LCA).

The tissue distribution and immunochemical properties of antigens recognized by two monoclonal antibodies 1.11.32 and 1.28.124 define the sheep analogue of the leucocyte common antigen found in rat, man and mouse. Histological and immunofluorescent studies show that this antigen is found on all lymphocytes, as well as other leucocytes but is absent from non-leucocytic cells. Immunochemical data show that a series of proteins of high molecular weight (190,000-225,000) are recognized, and histological studies show the presence of this antigen on a subpopulation of fetal liver cells as early as Day 27-30 of gestation, and on all fetal thymocytes from Day 40 of gestation.

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PubMed1985

Characterization of two sheep lymphocyte differentiation antigens, SBU-T1 and SBU-T6.

The monoclonal antibodies 25.91 and 20.27 define two lymphocyte cell surface antigens of sheep. 25.91 is reactive with 60-80% of lymphocytes and 98% of thymocytes, and only stains surface immunoglobulin-negative peripheral lymphocytes. 25.91 immuno-precipitates a 67,000 MW protein from lymphocyte lysates under both reducing and non-reducing conditions, whereas immunoprecipitation of thymocyte lysates reveals a 67,000, 62,000 MW complex. The tissue distribution and molecular weight analysis reported here for the antigen recognized by 25.91 indicate that this antigen is the sheep homologue of the human T1 and mouse Ly 1 antigens. The monoclonal antibody 20.27 is reactive with 80% of thymocytes and the majority of cell surface immunoglobulin-positive peripheral blood lymphocytes (B cells), but is unreactive with peripheral blood T cells. 20-27 also stains Langerhans cells in skin tissue sections and large dendritic-like cells in the paracortex sections and large dendritic-like cells in the paracortex of lymph node tissue sections. Immunoperoxidase staining of thymus tissue sections with 20.27 shows intense staining of cortical thymocytes and an absence of staining within the medulla. Molecular weight analysis of the 20.27 antigen reveals two major bands of 46,000 and 12,000 MW under both reducing and non-reducing conditions. The 20.27 antigen has properties resembling MHC class I-like antigens such as T6 in the human and TL in the mouse.

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PubMed1985

Surface antigens, SBU-T4 and SBU-T8, of sheep T lymphocyte subsets defined by monoclonal antibodies.

Monoclonal antibodies have been used to characterize molecules found on the surfaces of T cells of sheep. SBU-T4 and STU-T8 are present on 80-85% of thymocytes, absent from B lymphocytes, and present on two-thirds and one-third of lymph node T lymphocytes, respectively. Double-labelling of T lymphocytes shows that the populations recognized are mutually exclusive. Immunoprecipitation of the SBU-T4 antigen from thymocytes and T lymphocytes reveals a molecule which migrates on SDS-PAGE as a single band of 56,000 MW under both reducing and non-reducing conditions. Under reducing conditions, the SBU-T8 molecule migrates as two bands of 33,000 and 36,000 MW when immunoprecipitated from thymocytes, but only the higher MW band is present following immunoprecipitation from peripheral lymphocytes. Under non-reducing conditions, SBU-T8 migrates as dimers and other multiples. Based on immunofluorescent, immunochemical and immunohistological data, these molecules are considered to be the structural analogues of the marker molecules used to delineate T-helper and T-cytotoxic/suppressor lymphocyte subsets of other species.

Animals↗
PubMed1985

Sheep lymphocyte antigens (OLA). II. Major histocompatibility complex class II molecules.

A panel of monoclonal antibodies have been produced which recognize monomorphic determinants of sheep MHC Class II antigens, including an allogenically derived murine monoclonal antibody specific for the I-E gene product. Immunoprecipitation and SDS-PAGE analyses indicates that these monoclonal antibodies recognize a non-covalently associated glycoprotein complex of molecular weight 30-32 kDa (alpha chain) and 24-26 kDa (beta chain). One and two colour immunofluorescence was used to measure the distribution of these 'Ia-like' antigens on mononuclear cells from various lymphoid organs. They were found almost exclusively on lymphocytes expressing surface immunoglobulin (B lymphocytes) and on a small population of surface immunoglobulin negative cells. Most thymocytes were negative for Class II molecules while thymic epithelial cells were positive. The tissue distribution of Class II molecules was found to be similar to that described in man. Individual monoclonal antibodies displayed no variations in reactivity with the different tissues studied.

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