| 1. |
- Belfrage, Hans, et al.
(författare)
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Combined activation of murine lymphocytes with staphylococcal enterotoxin and interleukin-2 results in additive cytotoxic activity
- 1994
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Ingår i: Cancer Immunology and Immunotherapy. - 1432-0851. ; 38:4, s. 71-265
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Tidskriftsartikel (refereegranskat)abstract
- This report demonstrates that in vitro activation of murine spleen cells with interleukin-2 (IL-2) or the bacterial superantigen staphylococcal enterotoxin A (SEA) results in different patterns of activation and function of cytotoxic cells. Lymphokine-activated killer activity and antibody-dependent cellular cytotoxicity (ADCC) are mainly mediated by IL-2 activated natural killer (NK) cells. SEA is the most powerful T cell mitogen known so far and retargets cytotoxic T lymphocytes (CTL) to tumors expressing major histocompatibility complex (MHC) class II in staphylococcal-enterotoxin-dependent cellular cytotoxicity (SDCC). Culture of mouse spleen cells with SEA led to expansion and activation of T cells, which demonstrated strong SDCC activity and some NK-like cytotoxicity after 5 days in culture. Cell sorting revealed that both CD8+ and CD4+ T cells mediated SDCC but the former were more effective. Phenotypic analysis showed that SEA preferentially stimulated and expanded T cells expressing T cell receptor V beta 11, in particular CD8+ T cells. Combined activation with SEA and IL-2 resulted in simultaneous induction of T and NK cell cytotoxicity. Moreover, IL-2 had additive effects on SEA-induced SDCC. Combined treatment with SEA and IL-2 might therefore be an approach to induce maximal cytotoxicity against tumors and to recruit both T and NK cells in tumor therapy.
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| 2. |
- Hedlund, Katarina, et al.
(författare)
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Mycelial responses of the soil fungus, Mortierella isabellina, to grazing by Onychiurus armatus (collembola)
- 1991
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Ingår i: Soil Biology and Biochemistry. - 0038-0717. ; 23:4, s. 361-366
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Tidskriftsartikel (refereegranskat)abstract
- Hyphal morphology and extracellular enzyme production of the fungus Mortierella isabellina were studied during grazing by a soil Collembola, Onychiurus armatus. Grazing induced switching from a "normal" hyphal mode, with appressed growth and sporulating hyphae, to fan shaped sectors of fast growing and nonsporulating mycelium which developed extensive aerial mycelium. Specific protease and α-amylase activities were several times higher in grazed cultures where switching occurred compared with plates without switching. Increased protease activity was localized to switched sectors within the mycelium. On the basis of inhibitor studies, the protease of "normal" mycelium was classified as a metalloprotease. Switching induced activity of an additional serine protease. Anion-exchange chromatography showed that the two proteases had similar charges and, according to SDS-gclatine-PAGE. the molecular weight of the serine protease was 80.000. Switching to a fast growing hyphal mode could be one explanation for compensatory growth of grazed fungi.
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