https://www.ucl.ac.uk/%7Eucbzwdr/publications/Barres%20et%20al%20%28Cell%201992%29.pdf

Cell death and control of cell survival in the oligodendrocyte lineage

We have previously described the derivation of M1/70, a hybrid myeloma line secreting monoclonal rat anti-mouse cell surface antibody (Springer, T., Galfre, G., Secher, D. S. and Milstein, C, Eur. J. Immunol. 1978. 8: 539). We have now investigated the cellular distribution of this antigen using a 125I-labeled anti-rat IgG indirect binding assay, the fluorescence-activated cell sorter, autoradiography and precipitation of cell surface molecules. Screening with a tumor cell panel showed strong reactivity with a macrophage-like line but no reactivity with B or T lymphoma lines. In normal tissues, M1/70 antigen was found to be present in small amounts on spleen and exudate granulocytes and a subpopulation of bone marrow cells, in moderate amounts on spleen and blood monocytes and expressed in much larger amounts on spleen histiocytes and peritoneal exudate macrophages. In contrast, M1/70 antigen was found to be absent from erythroid and lymphoid cells. M1/70 antibody precipitated two polypeptides of 190 000 and 105 000 mol. wt. which were present in much greater amounts on peritoneal exudate macrophages than on spleen cells. The expression on phagocytes of two other antigens identified by monoclonal antibodies M1/69 and M1/9.3 was also examined. Monocytes and granulocytes expressed large amounts of M1/69 and low amounts of M1/70 antigen, while in peritoneal exudate macrophages this pattern was dramatically reversed. M1/70 thus defines a differentiation antigen on mononuclear phagocytes and granulocytes, the expression of which is specifically increased during monocyte maturation. This antibody is the first to be described which recognizes a discrete molecule specific to phagocytes.

Mac‐1: a macrophage differentiation antigen identified by monoclonal antibody

Cell-type-specific markers for distinguishing and studying neurons and the major classes of glial cells in culture

Astrocyte proliferation and perivascular lymphocyte infiltration are conspicuous among the cellular changes in the active brain lesions of multiple sclerosis patients1. Recent observations have indicated that most of the perivascular lymphocytes are T cells2–4 which may be actively involved in the generation of the brain lesions. Much less is known about the significance of the proliferative astrocytes, although the fact that they produce an interleukin-1 (IL-1)-like factor that enhances the release of interleukin-2 by T lymphocytes5,6, may provide a clue. We show here that rat astrocytes are able to present antigen to T lymphocytes in a specific manner which is restricted by the major histocompatibility complex (MHC) and that they can in particular activate myelin basic protein (BP)-specific, encephalitogenic T-cell lines. Only on such interaction do astrocytes express Ia antigens in easily detectable amounts. Antigen presentation by astrocytes may have a central role in the generation of immune responses in the brain.

Astrocytes present myelin basic protein to encephalitogenic T-cell lines.

Publisher Summary Changes in antigen molecules that resulted in enhanced or decreased uptake by the phagocytes resulted in higher or lower immune responses, respectively. After the development of methodologies for obtaining live exudate cells rich in phagocytes and for pulsing these with antigen, the immune response to macrophage-associated antigens was possible to assay, using combinations of in vivo and in vitro methods. The presentation of antigen bound to live macrophages to the lymphocytes was a highly efficient mode of generating an immune response. In the marine system, the requirement for phagocytes or other acc|essory cells was such that as little as 1% contamination with phagocytes still enabled a T-cell proliferative response to develop. Thus, depletion procedures had to be extremely efficient. Macrophages are definitely involved in some response to many of the conventional polyclonal stimuli. Involvement of the macrophage may be by way of secreted active molecule. Fc fragments of Ig act as a polyclonal stimulant only after a processing of the fragment by the macrophages. The developments in macrophage biology over the past few years were not predicted till 1972.

The regulatory role of macrophages in antigenic stimulation. Part Two: symbiotic relationship between lymphocytes and macrophages.

Mouse lymph node cells were exposed to carbonyl iron and a magnet to remove phagocytic cells, and passed over Sephadex G-10 and nylon wool and incubated for 12 h on plastic to remove adherent cells and their precursors. More than 99 % of the cells in this macrophage-depleted population (which constituted 3-5 % of the starting population) were Thy-1+ and Ly-1+, while less than 2 % were Ly-2+. These cells usually did not synthesize detectable amounts of DNA when cultured with concanavalin A and responded poorly to phytohemagglutinin. These proliferative responses were completely reconstituted by small numbers of syngeneic or allogeneic peritoneal cells, purified peritoneal macrophages or cells from tertiary cultures of mouse embryo ‘fibroblasts’, but not by 3T3 cells, P815 mastocytoma cells or Nulli SCC-1 embryonal carcinoma cells, or by 2-mercaptoethanol. The reconstituting peritoneal cells were Thy-1−, Ia+ and present in nu/nu mice; although they had to be alive to reconstitute, they did not have to divide. These results are consistent with the hypothesis that T cell proliferation induced by lectins, like that induced by antigens, may involve the dual recognition of stimulating ligand in association with major histocompatibility complex (la) determinants.

S. Habu

Papers

Accessory cell dependence of lectin-induced proliferation of mouse T lymphocytes.