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F J Keuning

Publications and source records attributed to F J Keuning.

13 recordsLinked to original sources
PubMed1983

Immune suppression and histophysiology of the immune response. I. Cortisone acetate and lymphoid cell migration.

Seven daily intramuscular (im) injections of cortisone acetate (25 mg/Kg b.w.) given to rats or rabbits produced, (i) a pronounced reduction in the numbers of small lymphocytes in thymus-independent areas, (ii) atrophy of the thymic cortex, (iii) atrophy of germinal centres and (iv) a consequent depressed production of germinal centre-derived cells. Lymphocyte depletion was not caused by cell lysis. Moreover cell traffic between peripheral lymphoid organs did not seem to be altered. A revival of the depressed germinal centres in cortisone-treated (inbred) rats could be achieved by a transfer of bone-marrow cell suspensions from normal, cortisone-treated or T-cell-deprived animals. It was concluded that cortisone acetate arrests the migration of B-lymphocytes from the bone marrow to germinal centres in peripheral lymphoid organs, and that the accumulations of lymphoid cells in the bone marrow of cortison-treated animals might be composed of immature or mature T- and B-lymphocytes.

Animals↗
PubMed1980

The graft-versus-host reaction in the rabbit spleen. Ultrastructural evidence for two differentiated T-cell lines.

Lethally irradiated (900 rads), bone-marrow-protected rabbits were given allogeneic thymocytes intravenously. Autoradiography by means of local splenic infusion of (H3) thymidine revealed progeny of two differentiated T-cell lines. Electron microscopy confirmed these observations in detail. An analogy with cellular immunity reactions in an "isolated T-cell system", performed in draining lymph nodes after a variety of antigenic stimuli is presented. The functional properties of these T-blasts and their lymphoid descendants are discussed.

Animals↗
PubMed1980

A T-dependent plasma cell response: part of a graft-versus-host and host-versus-graft reaction in the rabbit spleen.

B-cell reactivity, as expressed in a plasma cell reaction may be part of a graft-versus-host or host-versus-graft reaction. Cell transfer experiments were able to prove this. Histological evidence is presented for the occurrence of the so-called "allogeneic effect" during a graft-versus-host or host-versus-graft reaction in the rabbit spleen. Cell suspensions containing both T- and B-cells give rise to a cellular and a humoral immunity reaction component upon transfer to histoincompatible recipients. This can also occur during a graft-versus-host reaction. This B-cell response is T-cell dependent.

Animals↗
PubMed1978

Site of initiation of the plasma cell reaction in the rabbit lymph node. Ultrastructural evidence for two distinct antibody forming cell precursors.

Two times sublethal total body-X-irradiation with weekly local thymus irradiation established a T-cell deprived experimental model in rabbits. Humoral immunity reactions in draining lymph nodes have been analyzed histologically and at the submicroscopical level after challenge with Salmonella Java vaccine, horse spleen ferritin, horse-gamma-globulin, a chemical sensitizer oxazolone (2 phenyl-4-ethoxymethylene-5-oxazolone) and after skin allografting respectively. The time sequence studies in these animals with an 'isolated B-cell system' are compared with similar experiments in normal non-irradiated rabbits. The site of initiation of the thymus-independent and thymus-dependent plasma cell response is established in the lymph node. The (ultra)structural features of the antibody forming (-B-)cell precursors, the marginal zone cells, are described and discussed. The differentiating off-spring of two (sub)microscopically recognizable plasma cell lines is presented.

Animals↗
PubMed1978

Histophysiology of cellular immunity reactions in B-cell deprived rabbits. An X-irradiation model for delineation of an 'isolated T-cell system'.

Three times sublethal total body X-irradiation with thymus shielding--at 2 weeks' intervals--delineated a temporarily B-cell deprived animal model, only reconstituted with recently thymus-derived cells. The thymusdependent areas of peripheral lymphoid tissue-repleted with T-cells--are described. The cellular immune capacity of these animals with an "isolated T-cell system" was analyzed by means of skin allografting. Histological and autoradiographic studies were performed in draining lymph nodes after a variety of antigenic stimuli: skin allografts, S. java vaccin, horse-gamma-globulin, horse spleen ferritin and a contact sensitizer (Oxazolone).

Animals↗
PubMed1978

Electron microscopy of cellular immunity reactions in B-cell deprived rabbits. Thymus derived antigen reactive cells, their micro-environment and progeny in the lymph node.

Three times sublethal total body X-irradiation with thymus shielding--at 14 days' intervals--established an 'isolated T-cell system'. Cellular immunity reactions in draining lymph nodes of rabbits have been analyzed at the ultrastructural level after challenge with horse spleen ferritin, the chemical sensitizer, 2-phenyl-4-ethoxymethylene-5-oxazolone and after skin allografting. A basic pattern of interdigitating cells (IDC) is described as a specific constituent of the thymus-dependent areas of peripheral lymphoid tissue. Their ultrastructural features and presumable functional relationship to the afferent loop of cellular immunity reactions are presented. The differentiation pathway of two T-cell lines is shown and discussed in relation to cellular and thymus-dependent humoral immunity reactions.

Animals↗
PubMedDate not supplied

Effects of drugs on immune responsiveness in rabbits.

The effects of chemotherapeutica: 6 mercaptopurine (6 MP), nitrogen mustard (HN2) and cyclophosphamide (Cy) on T and B cells were studied in standardized experimental systems. From the histological and immunological results it was concluded that: (a) A course of 9 daily 6 MP injections affected antibody production only when given after antigenic stimulation. Histologically figures of mitotic death were found among proliferating cells of plasmacellular-germinal centre-and specific cellular reactions. It was concluded that a net mitotic death of 50% would account for the observed immunological and histological effects; (b) HN2 and Cy affected antibody production itself when administered during a very restricted period (1 through 3 days after ag.). Histologically only morphological changes were found in differentiating immature plasmacells and interphase death of cells involved in germinal centre reactions. Loss of responsiveness depended on the degree of interphase death of follicular elements. Cy interfered with the formation of T helper cells in thymus-dependent antibody production; (c) L-Asparaginase (1,000 U) only prevented the origination of T-helper cells. Neither antibody-producing cells nor their precursors were affected.

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