Reed-Sternberg cells in Hodgkin's lymphoma present features of cellular senescence.

Hodgkin's Lymphoma (HL) is one of the most prevailing malignancies in young adults. Reed-Sternberg (RS) cells in HL have distinctive large cell morphology, are characteristic of the disease and their presence is essential for diagnosis. Enlarged cells are one of the hallmarks of senescence, but whether RS cells are senescent has not been previously investigated. Here we show that RS cells have characteristics of senescent cells; RS cells in HL biopsies specifically express the senescence markers and cell cycle inhibitors p21Cip1 and p16INK4a and are negative for the proliferation marker Ki-67, suggesting that these cells have ceased to proliferate. Moreover, the RS-like cells in HL lines, stained specifically for senescence-associated ß-galactosidase (SA-ß-gal). Oxidative stress promoted senescence in these cells as demonstrated by their staining for p21Cip1, p16INK4a, p53 and γH2AX. Senescent cells produce copious amounts of inflammatory cytokines termed 'senescence-associated secretory phenotype' (SASP), primarily regulated by Nuclear Factor κB (NF-κB). Indeed, we show that NF-κB activity and NF-κB-dependent cytokines production (e.g., IL-6, TNF-α, GM-CSF) were elevated in RS-like cells. Furthermore, NF-κB inhibitors, JSH-23 and curcumin reduced IL-6 secretion from RS-like cells. Thus, defining RS cells as senescent offers new insights on the origin of the proinflammatory microenvironment in HL.

MHC class 2 deficiency and X-linked agammaglobulinaemia in a consanguineous extended family.

Manifestations of immunodeficiency within the same family are presumed to be the same disease. We report a consanguineous extended family where four patients have immunodeficiency, three have X-linked agammaglobulinaemia and one has major histocompatibility complex class 2 deficiency. Within one family, two rare genetic diseases with similar clinical manifestations can occur.

Regulation of the expression of CD45 isoforms in the Farage human B cell lymphoma line and its 10.6.1 subline.

Different B-cell neoplasias vary in the expression of CD45 isoforms. In the present study two sublines of a human B cell lymphoma- the original Farage line (Farage OL) and the Farage 10.6.1 subline were used to analyze the regulation of the expression of CD45 cell surface determinants. Cells of the Farage OL line constitutively expressed both CD45RO and CD45RA determinants on their cell surface. In contrast, the majority of the cells of the Farage 10.6.1 subline expressed CD45RA, and only few cells were CD45RO+. The low molecular spliced CD45 mRNA, characteristic for CD45RO was found in Farage OL cells, but was almost undetectable in Farage 10.6.1 cells. Following exposure to interleukin-4 (IL-4) a large proportion of the Farage 10.6.1 cells expressed CD45RO while in Farage OL cells the proportion of CD45RO+ was slightly reduced. The low molecular, spliced mRNA characteristic for CD45RO, was increased in Farage 10.6.1 cells following IL4 stimulation, but was slightly reduced in Farage OL cells. The molecular weight of CD45RA molecules produced by Farage cells varied from 185 kDa to 220 kDa while that of CD45RO molecules was 175 kDa. Preliminary attempts were made to determine a possible correlation between the expression of CD45RO and apoptosis in Farage cells. In both the Farage OL and Farage 10.6.1 cells the proportion of Bcl-2+ cells was lower among CD45RO+ cells than among CD45RO- cells. The present study indicates that IL4 has different effects on the alternative splicing of CD45 mRNA in two closely related B cell lymphoma lines. Thus, factors produced by the B lymphoma cells themselves may endow the cells with different patterns of responsiveness to a single stimulatory agent.

Enhancement of T cell receptor signaling by a mild oxidative shift in the intracellular thiol pool.

Exposure of T cells to the macrophage products hydrogen peroxide (HP) or L-lactate (LAC) was previously shown to enhance IL-2 production and to modulate glutathione (GSH) status. We now found that 50 microM HP and 30 mM LAC enhanced strongly the transcription from the IL-2 promoter in Jurkat T cells after stimulation with anti-CD28 together with or without anti-CD3 but not with anti-CD3 Abs alone. Therefore, we used anti-CD3 plus anti-CD28-stimulated cells to investigate the effect of the GSH reductase inhibitor 1, 3-bis(2-chloroethyl)-1-nitrosourea (BCNU) on the signal cascade. BCNU enhanced the transcription to a similar extent as HP or LAC. Lowering the intracellular GSH/GSH disulfide ratio by BCNU, HP, or NO resulted in all cases in the fulminant enhancement of Jun-N-terminal kinase and p38 mitogen-activated protein kinase but not extracellular signal-regulated kinase 1/2. Jun-N-terminal kinase and NF-kappaB activation was enhanced through pathways involving Rac, Vav1, PKCTheta, p56(lck), p59(fyn), and IkappaB kinases. In a cell-free system, the autophosphorylation of rFyn was stimulated by GSH disulfide but not by HP. These findings suggest that the oxidation of the cellular thiol pool may play a role as an amplifying mechanism for TCR/CD3 signals in immune responses.

Role of cysteine and glutathione in signal transduction, immunopathology and cachexia.

Abnormally low plasma cystine levels have been found in the late asymptomatic stage of HIV infection and several other diseases associated with progressive loss of skeletal muscle mass. The phenomenon is commonly associated with a low NK cell activity, skeletal muscle wasting or muscle fatigue and increased rates of urea production. In its extreme form, the negative nitrogen balance leads to overt cachexia and is associated with severe debilitation and psychological stress. The low NK cell activity is in most cases not life-threatening but may be disasterous in HIV infection, because it may compromise the initially stable balance between immune system and virus and trigger disease progression. This review summarizes briefly (i) the role of cysteine in the physiological regulation of body cell mass and the development of skeletal muscle wasting, and (ii) the role of glutathione in the immune system.

Pathways controlling the expression of surface CD21 (CR2) and CD23 (Fc(epsilon)IIR) proteins in human malignant B cells.

The aim of the present study was to analyze the pathways regulating the expression of CD21 and CD23 B-cell differentiation antigens on human malignant B cells. Exposure of Farage cells, derived from a human B-cell lymphoma, to phorbol 12-myristate 13-acetate (PMA) down-regulated CD21 and CD23 expression, while interleukin 4 (IL4) inhibited the expression of CD21 but augmented CD23 expression. When Farage cells were stained with either anti-CD21 or anti-CD23 monoclonal antibodies (mAb), subsequent exposure to IL4 failed to change the staining of the cells, indicating that IL4 did not affect the turnover of CD21 and CD23 molecules. Inhibition of protein synthesis with cycloheximide (CXM) had no effect on the expression of CD21 molecules, but abrogated their down-regulation by IL4, suggesting that IL4 induced the synthesis of proteins which modify the processing of CD21 molecules. The inhibitory effect of IL4 on the expression of CD21 and its augmentary effect on the expression of CD23 was abrogated by H7 (1-(5-Isoquinolinylsulfonyl)-2-methylpiperazine), an inhibitor of serine protein kinase. Staurosporine, an additional inhibitor of serine kinases also abrogated the effect of IL4 on CD23 expression. H8 (N-(2-[Methylamino]ethyl)-5-isoquinolinesulfonamide), a preferential inhibitor of protein kinases A and G, and genistein, an inhibitor of tyrosine kinases had no effect on IL4-induced modulation of CD21 and CD23 in Farage cells. The exposure of B-chronic lymphocytic leukemia (CLL) cells to PMA reduced the expression of CD21, but increased the expression of CD23. IL4 had no effect on the expression of CD21 on CLL-cells but strongly enhanced the level of CD23. H7, H8 and genistein each abrogated to a different extent the effect of IL4 on the expression of CD23 by CLL-cells. These data indicate that activation of serine/threonine kinases in malignant B cells inhibited the production of CD21 proteins, while different protein kinases appeared to be involved in up- and down-regulation of CD23 in different B lymphocytes.

The mechanism of interleukin 4-induced down-regulation of CD38 on human B cells.

Exposure of Farage, a human B-cell line, to interleukin 4 (IL4) reduced the amount of CD38 antigen on the surface of the cells and in cell lysates. No evidence was obtained for accelerated breakdown, shedding, or internalization of CD38 molecules following IL4 treatment, nor the accumulation of CD38 molecules in the cell interior. The inhibition of protein synthesis with cycloheximide (CXM) diminished the down-regulation of CD38 induced by IL4. CXM decreased the expression of CD38 in Farage cells with arrested mitosis, and IL4 failed to further reduce CD38 expression. Staurosporine, an inhibitor of serine/threonine protein kinases, and H7 (1-(5-isoquinolinylsulfonyl)-2-methylpiperazine), a preferential inhibitor of protein kinase C (PKC), abrogated the effect of IL4 on CD38, while inhibitors of other serine protein kinases W7 (N-(aminohexyl)-5-chloro-1-naphthalenesulfoamide) and H8 (N-(2-[methylamino]ethyl)-5-isoquinolinesulfonamide) failed to interfere with the effect of IL4. Phorbol 12-myristate 13-acetate (PMA), an activator of PKC, resembled IL4 in decreasing the expression of CD38, and either staurosporine or H7 abolished this effect. Genistein, an inhibitor of tyrosine kinases, increased the expression of CD38, but failed to abrogate the inhibitory effect of IL4 on CD38. It is concluded that serine/threonine protein kinases mediated the IL4-induced down-regulation of the expression of CD38 molecules in B cells.

Kinetics of the pleiotropic effect of interleukin 4 on the surface properties of human B-lymphoma cells.

Striking antigenic changes were elicited by interleukin 4 (IL-4) in the Farage human B-cell lymphoma line. After 2 days of incubation with IL-4 the expression of CD23, CD54 (ICAM-1), CD58 (LFA-3) was increased while the levels of CD21, CD22, CD38 were diminished. Prolonged incubation of Farage cells with IL-4 for 6-8 days led to increased expression of CD11a (LFA-1) CD39, CD40, and to disappearance of CD21 and CD38. The modulation of antigenic properties of Farage cells was associated with enhancement of their homotypic adhesiveness and the formation of giant clumps of cells. The recovery of Farage cells which had been exposed to IL-4 for six days was not complete and eleven days after withdrawal of the cytokine, these cells still displayed a lower level of CD21 and of CD38 than control cells. Cycling and non-cycling cells did not appear to differ in their antigenic properties, indicating that modification of the antigenic profile did not result from cell selection or cell arrest. These results showed that the pleiotropic effect of IL-4 on various cell surface structures on malignant human B cells proceeds at different rates suggesting that distinct metabolic pathways may regulate their expression.

The effect of IL-4 on the phenotype of a human B-cell lymphoma line (Farage) lacking immunoglobulin expression.

Farage cells do not express surface immunoglobulins (sIg) but display a high level of CD19, CD21, CD22, CD23, CD39, CD40 B-cell antigens, and various adhesion proteins, such as CD11a (LFA-1), CD29 (VLA-4), CD44, CD54 (ICAM-1), and CD58 (LFA-3). The phenotype of Farage resembled that of EBV-LCL but differed from the phenotype of Burkitt's lymphoma lines, which were CD39- CD44-, expressed a high level of CD38, and either lacked CD21 or were weakly positive. Exposure to IL-4 augmented the concentrations of CD23 and of adhesion proteins on the surface of Farage cells but diminished the expression of CD21, CD22, and CD38. IL-4 did not induce the expression of sIg on Farage cells and failed to affect the level of HLA-DR. IL-2 and TPA did not alter the level of CD21 and adhesion proteins on Farage cells. Although IL-4 induced unique changes of the antigenic pattern in Farage, no significant effect on the phenotype of Burkitt's lymphoma lines was detected after IL-4 treatment. The present study indicates that the responsiveness of B cells to IL-4 is not determined by the expression of sIg but rather is associated with the antigenic profile characteristic for non-germinal center B lymphocytes.