RESUMO
Monoclonal antibodies to cholera toxin were obtained. They do not cross-react with the termolabile toxin (LT) of Escherichia coli, ricin, diphtherial toxin, staphylococcus enterotoxins of SEA, SEB, SEI, SEG, or the lethal factor and protective antigen of the anthrax toxin. Pairs of antibodies for the quantitative measurement of the cholera toxin in sandwich enzyme immunoassay (EIA) were selected. The detection limit of the toxin is 0.2 ng/ml for plate EIA and 0.44 ng/ml for microchip EIA. The presence of milk, broth, or surface water in the toxin samples does not reduce the sensitivity of EIA.
Assuntos
Anticorpos Antibacterianos/imunologia , Anticorpos Monoclonais/imunologia , Toxina da Cólera/imunologia , Anticorpos Monoclonais/isolamento & purificação , Toxinas Bacterianas/imunologia , Reações Cruzadas , Proteínas de Escherichia coli/imunologia , Técnicas Imunoenzimáticas , Análise em MicrossériesRESUMO
The production of interleukin 2 by rat splenocytes, stimulated with Con A in serum-free medium, was studied. Under optimal conditions the stimulation in serum-containing and serum-free media resulted in identical interleukin 2 titers. The addition of phorbol myristate acetate prior or simultaneously with Con A did not augment interleukin 2 production. In contrast, preincubation of lymphocytes in serum-free medium for 24-36 hrs brought about a 8-10-fold increase of interleukin 2 titer. The interleukin 2 titer 4 hrs after the induction of preincubated lymphocytes with Con A was about 20% of maximal activity. The possible mechanism of early interleukin 2 production is under discussion.
Assuntos
Interleucina-2/biossíntese , Animais , Células Cultivadas , Concanavalina A/farmacologia , Meios de Cultura , Cinética , Ativação Linfocitária/efeitos dos fármacos , Linfócitos/imunologia , Ratos , Ratos Endogâmicos , Baço/imunologia , Acetato de Tetradecanoilforbol/farmacologiaRESUMO
Flow cytometry was used to demonstrate that cultured human melanoma BRO cells expressed membrane-bound tumour necrosis factor-alpha (TNF-alpha) and were able to release TNF-alpha upon treatment with glucosaminylmuramyl dipeptide (GMDP). The released TNF-alpha was shown to prime melanoma cells, previously unable to respond to GMDP by increasing expression of melanoma-associated antigens, making them sensitive to GMDP treatment.
Assuntos
Acetilmuramil-Alanil-Isoglutamina/análogos & derivados , Adjuvantes Imunológicos/farmacologia , Melanoma/metabolismo , Fator de Necrose Tumoral alfa/fisiologia , Acetilmuramil-Alanil-Isoglutamina/farmacologia , Animais , Antígenos de Neoplasias/biossíntese , Antígenos de Neoplasias/efeitos dos fármacos , Sistema Livre de Células/fisiologia , Meios de Cultivo Condicionados/farmacologia , Citometria de Fluxo , Humanos , Melanoma/imunologia , Camundongos , Células Tumorais CultivadasRESUMO
T-cell growth factor (interleukin 2) was partially purified from the conditioned medium from Con A-stimulated rat splenocytes. It had the molecular weight of 23,000 according to gel filtration and in the range of 17,000-18,000 daltons according to PAGE in the presence of SDS. The molecular forms of IL 2 exhibited isoelectric points (pI) of 5.4-5.8 (major peak), 4.3-4.5 and 6.5-6.8 (minor peaks). T-cell growth-promoting activity was remarkably stable to temperature, pH, SDS and 2-ME treatments. Rat IL 2 did not bind to immobilized Con A, WGA, RC 1, and fucose-binding protein. The conditioned medium also contained the inhibitor of IL 2-dependent T-cell proliferation.
Assuntos
Interleucina-2/análise , Animais , Cromatografia em Gel , Cromatografia por Troca Iônica , Eletroforese em Gel de Poliacrilamida , Feminino , Interleucina-2/isolamento & purificação , Focalização Isoelétrica , Masculino , Ratos , Ratos Endogâmicos , Baço/citologiaRESUMO
Flow cytometry was used to show that biologically active N-acetylglucosamine-containing muramylpeptides (GMPs) induced in vitro dose-dependent increase in the expression of tumor-associated antigens (TAAs) characteristic for colon and mammary gland carcinomas, melanoma and lung adenocarcinoma. Forty to two hundred percent enhancement in TAA-expressing cells was observed after 18-48 h incubation with GMPs. In contrast, MHC class I antigen expression was not altered. Using MTT and chromium-release assays, melanoma cells treated in vitro with GMDP were shown to be more susceptible to killing by peripheral blood cells of healthy donors than non-treated cells. Fractionation of blood cells revealed that platelets were responsible for this effect.
RESUMO
We studied the effect of combined treatment with cisplatin, glucosaminylmuramyl dipeptide, and TNF-alpha on viability of MCF-7, U-937, B16, and L-929 tumor cells, Ehrlich ascites carcinoma cells, and normal cells (human peripheral blood lymphocytes, peritoneal macrophages, and mouse bone marrow cells). Glucosaminylmuramyl dipeptide was nontoxic for normal and tumor cells, but promoted death of tumor cells after administration in combination with cisplatin and/or TNF-alpha. At the same time, glucosaminylmuramyl dipeptide did not modulate the cytotoxic effect of individual or combined treatment with cisplatin and TNF-alpha on normal cells. Administration of glucosaminylmuramyl dipeptide to cultured MCF-7 cells 20 h before the study increased the potentiating effect of muramyl peptide.