Interleukin 4 alone and with gamma-interferon or alpha-tumor necrosis factor inhibits cell growth and modulates cell surface antigens on human renal cell carcinomas.

Immune cytokines have been shown to play important roles in regulating immune cell functions as well as neoplastic cells. Interleukin-4 (IL4), primarily known as a B-cell growth factor, can also activate and differentiate other immune cells. This cytokine has recently been shown to have immunotherapeutic benefit in tumor-bearing hosts. The present study assessed the effect on human renal cell carcinoma cell lines of recombinant IL4 alone and in combination with recombinant gamma-interferon (IFN) or recombinant alpha-tumor necrosis factor (TNF). IL4 inhibited cell growth of all lines at 250-500 units/ml in a differential manner. Expression of IL4 receptors was demonstrated on renal cell carcinomas. Overall, IFN (500 units/ml) alone inhibited cell growth; however, TNF (500 units/ml) was not as strong an inhibitor. When IL4 was combined with IFN or TNF there was a significant augmentation of cell growth inhibition and modulation of cell morphology of the cell lines. Tumor-associated ganglioside antigens (NeuAc alpha 2-3Gal beta 1-4Glc beta 1-1'Cer, NeuAc alpha 2-8NeuAc alpha 2-3Gal beta 1-4Glc beta 1-1'Cer, GalNAc beta 1-4 (NeuAc alpha 2-3)Gal beta 1-4Glc beta 1-1'Cer, and GalNAc beta 1-4(NeuAc alpha 2-8NeuAc alpha 2-3)Gal beta 1-4Glc beta 1-1'Cer) HLA class I, HLA-DR, and beta 2-microglobulin on the cell surface of renal cancer lines were assessed by flow cytometry and radiometric binding assay. IL4 alone or in combination with other cytokines modulated HLA class I and HLA-DR expression. IL4 and IFN consistently enhanced NeuAc alpha 2-8NeuAc alpha 2-3Gal beta 1-4Glc beta 1-1'Cer and GalNAc beta 1-4(NeuAc alpha 2-8NeuAc alpha 2-3)Gal beta 1-4Glc beta 1-1'Cer expression on individual cell lines. The study demonstrated that IL4 alone or in combination with other cytokines can significantly inhibit growth, and modulate the expression of surface major histocompatibility and tumor-associated antigens of renal cell carcinomas.

Modulation of human melanoma cells by interleukin-4 and in combination with gamma-interferon or alpha-tumor necrosis factor.

Immune cytokines have been shown to play important roles in regulating immune cell functions. Interleukin-4 (IL4), originally described as a B-cell growth factor, is known to activate and differentiate other immune cells. IL4 has been given as an immunotherapeutic to tumor-bearing hosts. In this report, we set out to determine whether IL4 can directly modulate growth and expression of surface antigens on human melanoma cells. The effect of recombinant IL4 alone and in combination with recombinant gamma-interferon (IFN) or recombinant alpha-tumor necrosis factor (TNF) on melanoma cell lines was examined. IL4 significantly inhibited cell growth of all cell lines examined at 100-500 units/ml; but a dose-dependent differential response to individual cell lines occurred. The effect of IL4 was augmented by combination with IFN or TNF. Melanoma-associated ganglioside antigens (GM3, GD3, GM2, GD2) and human leukocyte antigen class I and DR on the cell surface of melanoma cells were assessed by flow cytometry and/or a radiometric binding assay. IL4, IFN, or TNF alone enhanced human leukocyte antigen class I, DR, and beta 2-microglobulin antigen expression. IL4 alone and in combination with IFN or TNF increased the GM3/GD3 ratio expression. GD2 was enhanced significantly by IL4, IFN, and TNF. Pretreatment of melanoma with IL4 or with other cytokines prior to stimulation with peripheral blood lymphocytes significantly enhanced mixed lymphocyte tumor reaction activity as compared with non-treated melanoma used as stimulators. These studies demonstrate that IL4 alone or in combination with IFN and TNF can modulate melanoma growth activity and surface antigen expression to a more differentiated and immunogenic phenotype.

Neutron reflection study of a water-soluble biocompatible diblock copolymer adsorbed at the air/water interface: the effects of pH and polymer concentration.

The effect of varying both the solution pH and copolymer concentration on the structure of layers of poly[2-(methacryloyloxy)ethyl phosphorylcholine-block-2-(dimethylamino)ethyl methacrylate] copolymer (denoted as MPC(30)-DMA(60), M(n) = 18,000) adsorbed at the air/water interface is studied using surface tension and specular neutron reflection. The surface structure of the adsorbed diblock copolymer is represented by a dense layer of 10-15 A on the air side, accompanied by a loose layer of 20-30 A extending into the aqueous phase. Although the uniform layer model generally provided a reasonable description of the adsorbed copolymer chains, some deviations were observed. A more detailed analysis showed that the distribution of the copolymer across the interface required a minimum of three layers to take into account the structural inhomogeneities. Refinement of the structural distributions involved the combined fitting of partially deuterated copolymer in null reflecting water and D(2)O and the fully hydrogenated copolymer in D(2)O, leading to a substantial improvement in the reliability of the structural profiles obtained. The data analysis showed an increase in surface excess at higher copolymer concentrations and at more alkaline pH. However, the copolymer layer was fully immersed in water under all conditions studied. Because the surface excess showed a steady increase across the cmc over the high pH range, we speculate that copolymer adsorption above the cmc involves the formation of surface micellar aggregates under these conditions.

Structural and functional changes associated with modification of the ubiquitin methionine.

The effects of oxidation and cleavage of Met-1 of ubiquitin on conformation and biological activity were individually investigated. Proton NMR studies demonstrated that oxidation to the sulfone led to restricted structural perturbations at neutral pH, particularly in the vicinity of Ile-61. Below pH 3, in the presence of acetic acid, oxidation to the sulfone facilitated a conformational expansion demonstrable by retardation on gel electrophoresis and CD changes below 210 nm. The predominant phase of the low-pH transition did not involve significant changes in alpha-helix content, indicating the capacity of ubiquitin for limited structural transitions. Cleavage of Met-1 by CNBr, on the other hand, was associated with a global unfolding transition below pH 4 that involved a major loss of alpha-helix. Differences in the behavior of the native and des-Met proteins at low pH indicate that Met-1 contributes a minimum of 3.4 kcal/mol to the stability of the native conformation. Two Met-1 sulfoxide isomers, of markedly different conformational stability, were formed by treatment of ubiquitin with H2O2. One isomer was similar in stability to the sulfone, while the other was intermediate in stability between the sulfone and des-Met proteins, the differences potentially interpretable in terms of the geometry of the Met-1-Lys-63 hydrogen bond. The overall activities of the oxidized and des-Met derivatives in ATP-dependent proteolysis differed subtly from that of native ubiquitin. The unresolved sulfoxides exhibited an approximately 50% increase in activity, while the sulfone and des-Met proteins exhibited a 50% decrease in activity at low concentrations and normal activity at higher concentration.(ABSTRACT TRUNCATED AT 250 WORDS)