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Biomedical subjects

M Simonsen

Publications and source records attributed to M Simonsen.

At least 55 records · Page 3Linked to original sources
PubMed1976

Allo-aggression in chickens. II. Cellular expression of the AA gene products.

B1-anti-B2 and B2-anti-B1 allo-antisera were raised by i.v. immunization of homozygous B1/1 and B2/2 chickens, respectively, with B1/2 cells of the following sources: peripheral blood leucocytes (PBL), erythrocytes, thymus cells and bursa cells. Purified suspensions of these all produced anti-B allo-antibodies which could both haemagglutinate red blood cells and strongly inhibit the GVH reactivity of blood lymphocytes of the original donor type. Absorption studies of the sera using cells of the same four sources showed that they could all completely remove the GVH inhibitory antibodies. A fact of particular importance is that B-haplotype determined antigens which are common to erythrocytes and lymphocytes seem to include the gene products of the allo-aggression locus, as earlier defined (Simonsen 1975).

Animals↗
PubMed1971

The factor of immunization in the rat. The effect of allogeneic immunization on graft-versus-host activity.

Using a popliteal lymph node weight assay the graft-versus-host activity of lymphocytes from donors immunized with allogeneic tissue has been assayed by comparison with that of lymphocytes from nonimmune donors. When the donors were immunized against weak histocompatibility antigens (non-AgB) the specific GVH activity of its lymphocytes was increased. This increase was greater if spleen cells rather than thoracic duct lymphocytes were the source of the donor cells used for assay. The increase in GVH activity was also greater if the standard immunization procedure of two successive skin allografts was followed by three boosting injections of allogeneic lymphoid cells. When donors were immunized against strong histocompatibility antigens the specific GVH activity of the donors' lymphocytes was slightly increased, was unchanged, or was actually decreased depending on the experimental situation. In donors rendered incapable of a humoral alloantibody response by whole body X-irradiation, immunization across a strong barrier was followed by little or no increase in the specific GVH activity of TDL. In the rat, as in other species, the increase in GVH activity after immunization is inversely proportional to the strength of the antigenic barrier involved.

Animals↗
PubMed1969

Antithrombin 3. Protection against death after injection of thromboplastin.

Intravenous injection of autologous lipoprotein (thromboplastin) or thrombin produced a lethal, hemorrhagic syndrome in chicken embryos. The embryos could be protected from this fatal result by injection of antithrombin III, an alpha(2)-globulin (molecular weight 60,000 to 80,000) purified from human, bovine, and guinea pig blood. Heparin also protected the embryos, but other inhibitors were less protective.

Alpha-Globulins↗
PubMed1969

The frequency of antigen-sensitive cells in tissue transplantation. A commentary on clonal selection.

Graft-vs.-host (GVH) reactions were performed in chicken embryos by intravenous injection of adult chicken blood dilutions, and the result was scored by weighing the spleens as well as by karyological identification of host and donor metaphases. From the frequency of detectable signs of GVH reaction when low doses of donor cells were injected into hosts containing one foreign allele of the B locus it is concluded that 1-2% must be a minimum estimate for the frequency of antigen-sensitive cells of a given specificity in this system. It is not found possible to reconcile the findings with the strictest form of clonal selection which postulates a single receptor specificity per clone of antigen-sensitive cells.

Animals↗