Nitric Oxide Promotes Growth and Major Histocompatibility Complex‐Unrestricted Cytotoxicity of Interleukin‐2‐Activated Rat Lymphocytes

Abstract

The effect of nitric oxide (NO) on growth and major histocompatibility complex(MHC)-unrestricted cytotoxicity of interleukin(IL)-2-cultivated rat spleen nonadherent mononuclear cells was examined. NO donor sodium nitroprusside (SNP) at relatively low concentrations increased magnitude, as well as duration of IL-2-induced proliferative response of nonadherent splenocytes. SNP effect depended completely on released NO, because it was prevented by NO scavenger haemoglobin, but not mimicked by expired SNP solution, unable to generate NO, or ferricyanide, a second breakdown product of SNP. Other NO donors - SIN-1, SNAP and GSNO failed to exert SNP-like growth-enhancing action, probably as a consequence of rapid NO generation, compared to sustained NO release by SNP. All NO-releasing chemicals at high concentration blocked IL-2-induced proliferation. Growth-promoting effect of SNP-derived NO was independent of guanilat cyclase activation, because dibutyryl cGMP did not affect IL-2-triggered splenocyte proliferation. Macrophage NO acted in a manner similar to SNP; at low concentrations it promoted IL-2-induced splenocyte growth, however higher amounts were suppressive. Cytotoxicity of IL-2-activated splenocytes against NK-sensitive K562 cell line was significantly increased when SNP was present during cultivation with IL-2. Proportion of NKR-P1+ and CD25+ cells, as well as per cell expression of these important activation molecules were increased upon SNP treatment, suggesting possible mechanism for the observed NO action.

Effects of Dietary Supplementation with Mulberry (Morus alba L.) Leaf Polysaccharides on Immune Parameters of Weanling Pigs

“…Similarly to the results of lymphocyte proliferation, the maximum effect was observed with the animals treated with low-dose MLPs (0.6 g/kg). For example, the MLT group showed superior results over the MHT group, which was in consonance with the findings of Badovinac et al [32], who showed that the effect of NO on lymphocyte proliferation was affected by its concentration, i.e., low concentrations of NO-stimulated lymphocyte proliferation, whereas high concentrations inhibited the proliferation.…”

Anti-inflammatory, Gastroprotective, and Cytotoxic Effects ofSideritis scardicaExtracts

“…The release of the cytosolic enzyme lactate dehydrogenase (LDH) reflects a loss of membrane integrity in dying cells, and it was assessed by a colorimetric assay as previously described [27]. Briefly, 100 µL of cell culture supernatant after treatment (cells grown in colorless medium) was mixed with 100 µL of solution containing 54 mM lactic acid, 0.28 mM phenazine methosulfate, 0.66 mM p-iodonitrotetrazolium violet, and 1.3 mM NAD + .…”

Novel platinum(IV) complexes induce rapid tumor cell death in vitro

“…16 MTT solution was added to cell cultures in final concentration of 0.5 mg / ml and cells were incubated for an additional 1 hr. Thereafter, the solution was removed and cells were lysed in dimethyl sulfoxide.…”

“…16 Briefly, 100 ll of cell culture supernatant (cells grown in colorless medium) was mixed with 100 ll of solution containing 54 mM lactic acid, 0.28 mM phenazine methosulfate, 0.66 mM p-iodonitrotetrazolium violet and 1.3 mM NAD. The pyruvate-mediated conversion of 2,4-dinitrophenylhydrazine into visible hydrazone precipitate was measured using an automated microplate reader at 492 nm.…”