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- Nelson, K, et al.
(författare)
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Separation of rat leukocytes by countercurrent distribution in aqueous two-phase systems. II. Subpopulations which mediate selective and nonselective lysis of normal and colon carcinoma target cells in vitro
- 1978
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Ingår i: Cellular Immunology. - : Elsevier BV. - 0008-8749. ; 37:2, s. 422-431
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Tidskriftsartikel (refereegranskat)abstract
- Spleen cells from WF rats immunized to allogeneic lymphoid cells or to syngeneic colon carcinomas and from unimmunized controls were separated by countercurrent distribution in aqueous two-phase systems. The cells were assayed for cytotoxicity to allogeneic fibroblasts or syngeneic colon carcinoma cells and to syngeneic fibroblasts in a 24-hr 51Cr-release assay. Cells from immunized rats which selectively lysed the specific target cells were repeatedly found in one area of the distribution separate from the majority of cells, which nonselectively lysed syngeneic fibroblasts as well. A similar subpopulation which nonselectively lysed all target cells assayed was recovered from the spleens of unimmunized rats. The cells were also assayed for the ability to lyse antibody-coated thymocytes in a 4-hr 51Cr-release assay. The peak of K cells was found to overlap partially that of cells with nonselective cytotoxicity.
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| 5. |
- Härfast, Bengt, 1950-
(författare)
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The effect of virus on the cytotoxic effector function of normal human lymphocytes
- 1979
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The cytotoxic effect of human peripheral blood lymphocytes (PBL) from healthy donors against mumps virus infected cells was studied by 5lCR-release assay. With several different cell fractionation techniques the effector cells were demonstrated to be undistinguishable from the lymphocytes responsible for antibody dependent cellular cytotoxicity (ADCC, K-cells) and from those responsible for natural cytotoxicity (NK cells). In these three cytolytic systems the effector cells have Fc receptors for IgG (FcR). While ADCC is dependent on antibody by definition, NK activity involves both antibody dependent and antibody independent mechanisms. To learn whether the killing of virus infected cells required antibody. Fab fragments of rabbit antibodies to human immunoglobulin were added to the PBL-target cell mixtures. This reagent failed to inhibit the virus dependent target cell lysis, implying that the; reaction was immunoglobulin independent. Binding of PBL to target cells by the virus did not seem to be sufficient to cause target cell lysis since a PBL subset which also adhered firmly to virus infected cells did not lyse those. However, a virus induced cross linking of effector cells and target cells may facilitate the expression of cytotoxicity. Exposure of PBL to small amounts of mumps virus results in an enhanced cytolytic activity against uninfected target cells. Also in this instance were the effector cells closely related to the K- and NK-cells. Virus dependent cytotoxicity was not due to an ADCC type of mechanism as it remained essentially unchanged when the FcR activity of the lymphocytes was experimentally modulated by exposure to antigen-antibody complexes. Mumps virions lacking both of their spike glycoproteins (HANA and F) failed to generate virus dependent cytotoxicity. Virions lacking only HANA also generated virus dependent cytotoxicity but their capacity to do so was markedly impaired. Solubilized preparations of viral spikes also enhanced cytotoxicity although to a lesser extent than intact virions. Anti-HANA antibodies, but not anti-F antibodies, abrogated cytotoxicity when incubated together with virus used for treatment of PBL. These experiments demonstrate that HANA was an essential component for the induction of cytotoxicity. The possible role of F remains to be established.
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| 6. |
- Ljungström, Inger, 1944-
(författare)
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Trichinella spiralis : formation of specific antibodies and modulation of the immune response
- 1979
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present study showed that Trichinella spiralis infection in human induced a specific antibody response including antibodies of IgM, IgA and IgG classes. Reactive sera were demonstrated from day 10 up to 2 years after onset of clinical symtoms. Experimental trichinosis resulted in cortical depletion of thymus and increased cell proliferation in T cell dependent and independent areas of spleen and lymph nodes during the early stage of infection. The capacity of the host to respond to an unrelated T cell dependent antigen given orally during the intestinal stage, was almost abolished at the local level in intestine, whereas the systemic response was depressed. Parenteral administration or oral immunization with unrelated T cell dependent antigens during the extraintestinal stage resulted in a depressed systemic antibody response. The humoral response to an unrelated T cell independent antigen was increased. Cellular immunity, measured as split heart allograft rejection, was depressed and the prolonged survival time was most pronounced during the intestinal stage. Spleen cell reactivity to polyclonal T cell activators and allogeneic stimulation was decreased and again the depression was most marked during the intestinal stage. Thus, T.spiralis infection profoundly affected the T cells during the intestinal stage and some depressive effects were observed also during the extraintestinal stage. T.spiralis infection enhanced the cholera toxin induced diarrhoea during the intestinal stage. This could probably be explained by the decreased absorption observed during the same period of infection. During the migration stage the intestinal secretory response to the enterotoxin was decreased. As the intestinal absorption was normal at this time the reduced fluid accumulation probably reflected a true inhibition of the secretory response.
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