Competition between citrate and heptapeptide DDSDEEN binding to DNA in presence of divalent cations

The binding of citrate and acidic peptide DDSDEEN with DNA in the presence of divalent cations is compared. Citric acid shows a higher number of binding sites on the DNA compared to the peptide; this is probably due to the bigger sitric hindrance of the peptide compared to the citric acid for the binding in the DNA grooves. Moreover. DNA preincubated with saturating amounts of citric acid is not available for the binding with successively added peptide. Therefore the peptide and citrate binding sites to some extent overlap.

An obligate role for T-cell receptor alphabeta+ T cells but not T-cell receptor gammadelta+ T cells, B cells, or CD40/CD40L interactions in a mouse model of atopic dermatitis

BACKGROUND

We recently described a murine model of atopic dermatitis (AD) elicited by epicutaneous sensitization with ovalbumin (OVA). The skin lesions in these mice were characterized by a dermal infiltrate consisting of eosinophils and T cells and by increased expression of the TH2 cytokines IL-4 and IL-5. Epicutaneous sensitization induces a rise in the levels of serum total IgE and OVA-specific antibodies, further indicating that it elicits a predominantly TH2 response.

OBJECTIVE

This study was undertaken to assess the roles of T cells, B cells, and CD40L-CD40 interactions in AD.

METHODS

Mice with targeted gene deletions were sensitized with OVA. Histologic and immunohistochemical examinations, as well as measurements of IL-4 mRNA, were performed on OVA-sensitized skin. Total and antigen-specific serum IgE levels were determined.

RESULTS

RAG2(-/-) mice, which lack both T and B cells, did not exhibit cellular infiltration, induction of dermal IL-4 mRNA, or elevation of serum IgE after OVA sensitization; all of these features were present in B-cell-deficient IgH(-/-) mice. T-cell receptor alpha(-/-) mice did not display cellular infiltration, IL-4 mRNA expression, or increased IgE levels after OVA sensitization, but these responses were elicited in T-cell receptor delta(-/-) mice after sensitization. Absence of CD40 had no effect on these responses.

CONCLUSION

These results suggest that alphabeta T cells, but not gammadelta T cells, B cells, or CD40L-CD40 interactions, are critical for skin inflammation and the TH2 response in AD.

Interleukin-1beta induces apoptosis in GL15 glioblastoma-derived human cell line

Interleukin 1-beta (IL-1beta) induces apoptosis in a glioblastoma-derived human cell line, exhibiting a poorly differentiated astrocytic phenotype. The apoptotic effect was demonstrated by analyzing nuclear morphology, in situ DNA fragmentation, and by ELISA detection of cytoplasmatic nucleosomes. We correlated the degree of differentiation of GL15 cells with the apoptotic response: 1) 4',6-diamidino-2-phenylindole staining, combined with glial fibrillary acidic protein (GFAP) immunofluorescence, showed that the cells with apoptotic nuclei express low levels of GFAP; and 2) at 13 days of subculture, in a more differentiated state, GL15 cells did not respond with apoptosis to IL-1beta. In this cell line, nonrandom chromosome changes and the expression of SV40 early region have been previously shown. The involvement of p42/p44 mitogen-activated protein kinase (MAPK) pathway in the induction of apoptosis by IL-1beta was hypothesized. Previous studies have shown that SV40 small T antigen partially inhibits phosphatase 2A, leading to an enhancement of the steady-state activity of p42/p44 MAPK pathway. PD-098059, specific inhibitor of p42/p44 MAPK pathway, counteracts the apoptotic effect of IL-1beta, whereas SB-203580, specific inhibitor of p38 stress-activated protein kinase (SAPK) pathway, is ineffective. The imbalance between MAPK and SAPK pathways has been proposed as a key factor in determination of cell fate. Our results demonstrate that a further stimulation of p42/p44 MAPK pathway can constitute a death signal in tumor cells in which genomic damage and MAPK pathway control alterations occur.

Immunosuppressive activity of 13-cis-retinoic acid in rats: aspects of pharmacokinetics and pharmacodynamics

Pharmacokinetics and pharmacodynamics of 13-cis-retinoic acid (13-cRA) administered at doses that suppress experimental autoimmune encephalomyelitis (EAE) have been investigated in rats. Serum concentration of the drug measured following oral administration of 37 mg/kg/12 h reached a peak of 1.8 x 10(-5) M in 2 h and linearly declined to 7.8 x 10(-7) M at hour 12. When spleen cells (SC) collected from 13-cRA-administered animals were cultured in vitro, their proliferative response to the T-cell mitogen concanavalin A (ConA) was suppressed and this effect was dependent on in vivo serum concentrations of the drug. In addition, in vitro exposure of antigen-specific T-cell lines to 13-cRA concentrations equivalent to those observed in vivo caused a dose-dependent suppression of the proliferation induced by the antigen as well as by T-cell mitogens. On a molar basis, 13-cRA showed a stronger in vitro immunosuppressive activity than two immunosuppressive agents used in human therapy, cyclosporin A and 6-mercaptopurin.

Impaired B cell maturation in mice lacking Bruton's tyrosine kinase (Btk) and CD40

Mutations in Bruton's tyrosine kinase (Btk) gene, in mice, result in reduced numbers and responses of peripheral B cells. Surface Ig-mediated signaling is defective in Btk mutant B cells as they do not proliferate upon slg cross-linking and lack thymus-independent (TI) type II responses. Signals through sIg and CD40 play a critical role in B cell maturation. To investigate the consequences of the lack of both Btk and CD40 on B cell development and function, mice were generated that were homozygous for targeted mutations in the Btk and the CD40 genes (BtkMCD40M). The CD40 mutation (CD40M) had a synergistic effect on the BtkM defects. In BtkMCD40M mice the number of B cells was reduced 3- to 4-fold compared to BtkM mice and mature B cells (IgMlow/IgDhigh) were virtually absent; serum levels of all Ig isotypes were diminished; and antibody responses to TI-I TI-II and thymus-dependent antigens were impaired. Furthermore, although wild-type BtkM and CD40M mice produced germinal centers in response to TI-I antigen, the BtkMCD40M mice did not. Maturational and functional B cell defects in BtkMCD40M mice may result from a combination of intrinsic B cell defects, lack of CD40L-dependent T cell help and microenvironmental defects. These data suggest that signals through Btk and CD40 are necessary for the production and maintenance of the mature B cell.

Induction of alloantigen-specific tolerance by B cells from CD40-deficient mice

Interaction between CD40 on B cells and CD40 ligand molecules on T cells is pivotal for the generation of a thymus-dependent antibody response. Here we show that B cells deficient in CD40 expression are unable to elicit the proliferation of allogeneic T cells in vitro. More importantly, mice immunized with CD40-/- B cells become tolerant to allogeneic major histocompatibility complex (MHC) antigens as measured by a mixed lymphocyte reaction and cytotoxic T-cell assay. The failure of CD40-/- B cells to serve as antigen presenting cells in vitro was corrected by the addition of anti-CD28 mAb. Moreover, lipopolysaccharide stimulation, which upregulates B7 expression, reversed the inability of CD40-/- B cells to stimulate an alloresponse in vitro and abrogated the capacity of these B cells to induce tolerance in vivo. These results suggest that CD40 engagement by CD40 ligand expressed on antigen-activated T cells is critical for the upregulation of B7 molecules on antigen-presenting B cells that subsequently deliver the costimulatory signals necessary for T-cell proliferation and differentiation. Our experiments suggest a novel strategy for the induction of antigen-specific tolerance in vivo.

CD40 expression and function in murine B cell ontogeny

The CD40 antigen, a member of the nerve growth factor/tumor necrosis factor receptor family, is expressed on all mature B lymphocytes and plays a crucial role in B cell activation, T cell-dependent antigen-driven isotype switching and germinal center formation. We have analyzed CD40 expression and function during mouse B cell development by examining B cell precursors in normal mice and in transgenic animals in which B cell development is frozen at discrete stages. These models included RAG-2-/- mice, and transgenic littermates that express a mu heavy chain and/or the bcl-2 proto-oncogene transgene. CD40 was undetectable at the pro-B cell stage, but was expressed, although at low levels, on pre-B cells. However, pre-B cells failed to respond to CD40 triggering either by expression of CD23 or by proliferation in the presence of IL-4. Overexpression of bcl-2 increased the density of CD40 expression on pre-B cells: these cells respond to CD40 ligation by expressing CD23 and by proliferating in the presence of IL-4.

Defective expression of early activation genes in cartilage-hair hypoplasia (CHH) with severe combined immunodeficiency (SCID)

Cartilage-hair hypoplasia (CHH) is an autosomal recessive disease of unknown etiology characterized by metaphyseal dysostosis, unpigmented hair, and defective cellular immunity. We studied peripheral blood mononuclear cells (PBMC) of a boy with CHH and combined immunodeficiency in an attempt to characterize further the immune defect in this disease. Stimulation of his PBMC with mitogens was associated with severely depressed IL-2 and interferon-gamma (IFN-gamma) synthesis and IL-2 receptor alpha-chain (IL-2R alpha) expression and resulted in poor lymphocyte proliferation that was only modestly upregulated by the addition of recombinant IL-2 (rIL-2). The defective proliferation and lymphokine synthesis were not corrected by the addition of phorbol myristate acetate (PMA) and ionomycin, agents that bypass receptor-mediated signalling, indicative of a distal abnormality. Importantly, the levels of mRNA encoding c-myc, IL-2R alpha, IL-2 and IFN-gamma were markedly decreased in patient lymphocytes stimulated with PMA+ionomycin as compared to control lymphocytes. The defect in the expression of these early activation genes was selective in that induction by mitogens of mRNA encoding other early activation gene products such as c-fos and c-jun was not impaired. These results suggest that the underlying defect in this patient and perhaps others with CHH may be an abnormality in a component of intracellular signalling pathways or in a trans-acting factor which regulates the expression of a selected number of early activation genes.

CD40-CD40 ligand (CD40L) interactions and X-linked hyperIgM syndrome (HIGMX-1)

Interactions between the B cell surface antigen CD40 and its ligand (CD40L) expressed on activated T cells play a critical role in isotype switching. This is illustrated by failure of isotype switching in patients with X-linked hyperIgM syndrome in whom the CD40L gene is mutated and by failure of isotype switching of CD40-deficient mice in response to T-cell-dependent antigens. We review these findings and discuss the signaling mechanisms of CD40 and the developmental control and transcriptional regulation of CD40L expression.

CD40 ligand/CD40 deficiency

CD40 is a surface antigen expressed on B cells. The CD40 ligand (CD40L) is expressed on activated T cells. Interaction between CD40 and CD40L is critical for proliferation and isotype switching in the context of a response to a T-cell-dependent antigen. Patients with X-linked hyper-IgM syndrome (HIGMX-1) in their CD40L gene are unable to switch from IgM to IgG, IgA and IgE. Mice with a disrupted CD40 gene fail to undergo isotype switching to T-cell-dependent antigens but respond normally to T-independent antigens.

CD40-deficient mice generated by recombination-activating gene-2-deficient blastocyst complementation

To study the role of B-cell antigen CD40 in immune responses, mouse embryonic stem (ES) cells in which both copies of the gene encoding CD40 had been disrupted by homologous recombination were injected in RAG-2 (recombination-activating gene-2)-deficient blastocysts to generate chimeras in which all mature lymphocytes are derived from the CD40-deficient ES cells. T- and B-cell number and phenotype were normal in the CD40-/- chimeras. However, B cells failed to proliferate and undergo isotype switching in vitro in response to soluble CD40 ligand (sCD40L) with interleukin 4 (IL-4) but responded normally to lipopolysaccharide (LPS) with IL-4. CD40-/- chimeras completely failed to mount an antigen-specific antibody response or to develop germinal centers following immunization with the T cell-dependent (TD) antigen keyhole limpet hemocyanin. In contrast, CD40-/- mutant mice responded normally to the T cell-independent (TI) antigens, 2,4,6-trinitrophenyl (TNP)-LPS and TNP-Ficoll. The most noticeable alteration in the serum immunoglobulin levels of young (6-8 weeks old) CD40-/- animals was absence of IgE and severe decrease of IgG1 and IgG2a. These results confirm the essential role of CD40- CD40L interactions in the antibody response to TD antigens and in isotype switching.

Molecular models of small phosphorylated chromatin peptides. Structure-function relationship and regulatory activity on in vitro transcription and on cell growth and differentiation

We previously reported the isolation of low molecular weight phosphorylated peptides from the chromatin of several tissues. The chromatin peptides show a regulatory activity on DNA in vitro transcription and on cell growth and differentiation. In this paper, we report a molecular model of the native peptides designed according to the structural information obtained by means of biochemical and mass spectrometry analysis: pyroGlu-Ala-Gly-Glu-Asp-Ser(P)-Asp-Glu-Glu-Asn. This or very similar sequences are present in many transcription factors; on the basis of the structural model we presented and of related protein sequences, we have synthesized the peptide pyroGlu-Asp-Asp-Ser-Asp-Glu-Glu-Asn. This peptide affects transcription rate in reconstituted systems in vitro and in isolated nuclei; moreover, it inhibits the growth of HL60 cells with a parallel stimulus of differentiation.

Possible specific activation of RNA synthesis in PC-12 cell isolated nuclei by small acidic peptides

Three synthetic peptides, pyro-Glu-Ala-Gly-Glu-Ser-Glu-Asp (Pep A), pyro-Glu-Ala-Gly-Glu-Glu-Glu-Ser-Asn (Pep B), and pyro-Glu-Asp-Asp-Ser-Asp-Glu-Glu-Asn (Pep C), bear sequences possibly belonging to components of a naturally occurring family of strongly related small acidic chromatin peptides involved in regulation of gene expression. In a crude nuclear fraction and in purified nuclei from PC-12 cells, Pep A and Pep B activate RNA synthesis, specifically acting on the RNA polymerase II transcription system. On the other hand, Pep C shows an inhibitory effect on RNA synthesis in purified nuclei but an activation in the crude nuclear fraction. Control experiments show that the serum thymic factor does not affect RNA synthesis in the crude nuclear fraction or in purified nuclei. A possible regulation by peptide phosphorylation via casein kinase II (more active in purified nuclei than in the crude nuclear fraction) is discussed.

Microbial superantigens induce NF-kappa B in the human monocytic cell line THP-1

Staphylococcal superantigens bind to MHC class II molecules and induce transcriptional activation of IL-1 beta and TNF-alpha genes in human monocytic cells. The understanding of the mechanisms by which superantigens activate cytokine gene expression is incomplete. In this study, we demonstrate that toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxins A and B induce the activation of NF-kappa B, a transcriptional enhancer that binds to sequences found in both the IL-1 beta and TNF-alpha promoters. Electrophoretic mobility-shift assays showed a rapid induction of nuclear proteins that bound to the consensus kappa B motif. Furthermore, TSST-1 potently stimulated chloramphenicol acetyltransferase (CAT) expression by THP-1 cells transfected with a consensus NF-kappa B-promoter CAT construct, indicative of induction of NF-kappa B enhancer function. Induction of both NF-kappa B DNA-binding proteins and NF-kappa B enhancer function was down-regulated by inhibitors of protein kinase C and protein tyrosine kinase, indicating a role for these protein kinases in the induction of NF-kappa B by MHC class II ligands. Using neutralizing antibodies, we demonstrated that after the stimulation of cells with TSST-1, TNF-alpha, but not IL-1 beta, acted to up-regulate binding of NF-kappa B to DNA and the activation of the NF-kappa B-promoter CAT construct. These results indicate that induction of NF-kappa B by superantigens is up-regulated in part by an autocrine loop involving TNF-alpha.

Microbial superantigens induce NF-kappa B in the human monocytic cell line THP-1

Staphylococcal superantigens bind to MHC class II molecules and induce transcriptional activation of IL-1 beta and TNF-alpha genes in human monocytic cells. The understanding of the mechanisms by which superantigens activate cytokine gene expression is incomplete. In this study, we demonstrate that toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxins A and B induce the activation of NF-kappa B, a transcriptional enhancer that binds to sequences found in both the IL-1 beta and TNF-alpha promoters. Electrophoretic mobility-shift assays showed a rapid induction of nuclear proteins that bound to the consensus kappa B motif. Furthermore, TSST-1 potently stimulated chloramphenicol acetyltransferase (CAT) expression by THP-1 cells transfected with a consensus NF-kappa B-promoter CAT construct, indicative of induction of NF-kappa B enhancer function. Induction of both NF-kappa B DNA-binding proteins and NF-kappa B enhancer function was down-regulated by inhibitors of protein kinase C and protein tyrosine kinase, indicating a role for these protein kinases in the induction of NF-kappa B by MHC class II ligands. Using neutralizing antibodies, we demonstrated that after the stimulation of cells with TSST-1, TNF-alpha, but not IL-1 beta, acted to up-regulate binding of NF-kappa B to DNA and the activation of the NF-kappa B-promoter CAT construct. These results indicate that induction of NF-kappa B by superantigens is up-regulated in part by an autocrine loop involving TNF-alpha.

Molecular basis of a multiple lymphokine deficiency in a patient with severe combined immunodeficiency

We have previously reported that the T lymphocytes of a child with severe combined immunodeficiency are defective in the transcription of several lymphokine genes that include IL2, IL3, IL4, and IL5, which encode interleukins 2, 3, 4, and 5 (IL-2, -3, -4, and -5). To determine whether the defect in the patient's T lymphocytes involved a trans-acting factor common to the affected lymphokine genes, we examined the ability of nuclear factors from the patient's T lymphocytes to bind response elements present in the regulatory region of IL2. Nuclear factor NF-kB, activation protein 1 (AP-1), OCT-1, and NF-IL-2B binding activity were normal. In contrast, the binding of the nuclear factor of activated T cells (NF-AT) to its response element in the IL2 enhancer and to an NF-AT-like response element present in the IL4 enhancer was abnormal. To ascertain whether the abnormal NF-AT binding activity was related to an impaired function, we transfected patient and control T lymphocytes with constructs containing the reporter gene encoding chloramphenicol acetyl transferase (CAT) under the control of the entire IL2 regulatory region or of multimers of individual enhancer sequences. CAT expression directed by the IL2 regulatory region or by a multimer of the NF-AT-binding site was markedly lower in the patient relative to controls. In contrast, CAT gene expression directed by a multimer of the OCT-1 proximal (OCT-1p)-binding site was equivalent in patient and controls. These results indicate that an abnormality of/or influencing NF-AT may underlie the multiple lymphokine deficiency in this patient.

A protein of the AP-1 family is a component of nuclear factor of activated T cells

Nuclear factor of activated T cells (NF-AT) is a transcriptional activator involved in the induction of IL-2 gene expression. The response element for NF-AT is a sequence localized between -285/-254 in the IL-2 regulatory region. The composition of NF-AT protein is still not fully elucidated. We demonstrate that, in normal human T cells, an AP-1 protein is a component of the NF-AT protein complex. This was evidenced by the ability of the AP-1 site to compete with the NF-AT site for binding to NF-AT and by the capacity of immobilized anti-Jun and anti-Fos antibodies to deplete NF-AT-binding activity from nuclear extracts of activated T cells. There was no detectable binding of in vitro translated Jun/Fos heterodimer (AP-1) to the NF-AT sequence, and the NF-AT sequence was unable to inhibit the binding of Jun/Fos to the AP-1 sequence. The presence of an AP-1 protein in the NF-AT protein complex may regulate NF-AT-binding activity through protein-protein interaction.

A protein of the AP-1 family is a component of nuclear factor of activated T cells

Nuclear factor of activated T cells (NF-AT) is a transcriptional activator involved in the induction of IL-2 gene expression. The response element for NF-AT is a sequence localized between -285/-254 in the IL-2 regulatory region. The composition of NF-AT protein is still not fully elucidated. We demonstrate that, in normal human T cells, an AP-1 protein is a component of the NF-AT protein complex. This was evidenced by the ability of the AP-1 site to compete with the NF-AT site for binding to NF-AT and by the capacity of immobilized anti-Jun and anti-Fos antibodies to deplete NF-AT-binding activity from nuclear extracts of activated T cells. There was no detectable binding of in vitro translated Jun/Fos heterodimer (AP-1) to the NF-AT sequence, and the NF-AT sequence was unable to inhibit the binding of Jun/Fos to the AP-1 sequence. The presence of an AP-1 protein in the NF-AT protein complex may regulate NF-AT-binding activity through protein-protein interaction.

Severe combined immunodeficiency with selective T-cell cytokine genes

A 4-y-old female with severe combined immunodeficiency disease had normal numbers of T cells in her circulation and normal T-cell subsets. However, her T cells proliferated poorly to mitogens and did not proliferate to antigens or to anti-CD3 MAb. IL-2 receptor expression was normal, but IL-2 synthesis was undetectable. The addition of recombinant IL-2 to a mitogen-stimulated culture resulted in normalization of the proliferative response. Northern blot analysis of total RNA derived from the patient's T cells revealed a weak or absent expression of mRNA coding for IL-2, IL-3, IL-4, and IL-5. In contrast, there were normal amounts of mRNA coding for granulocyte-macrophage colony-stimulating factor. Tumor necrosis factor and IL-6 production were also normal. Nuclear run-on transcriptional assays revealed markedly decreased levels of newly initiated nuclear transcripts coding for IL-2, IL-3, IL-4, and IL-5 and normal levels of granulocyte-macrophage colony-stimulating factor transcripts in the patient relative to control lymphocytes. Gel retardation assays suggest that the NFAT-1 nuclear transcription complex is abnormal in this patient. These results indicate that the patient suffers from a defect that affects the transcription of multiple T-cell lymphokines and suggest that abnormalities affecting the production of T-cell lymphokines may underlie some of the primary immunodeficiency diseases.

Developmental regulation of transmembrane signaling via the T cell antigen receptor/CD3 complex in human T lymphocytes

We have examined transmembrane signaling events via the TCR/CD3 complex (TCR/CD3) at various stages of T cell development for evidence of developmental regulation. Engagement of TCR/CD3 induced defective activation of phospholipase C (PLC) in thymocytes relative to peripheral blood T lymphocytes. The defect in PLC activation via TCR/CD3 was restricted to immature thymocytes (CD3low, CD4+CD8+). Mature thymocytes (CD3high, CD4+CD8-/CD8+CD4-) were similar to PBL in signaling via TCR/CD3. Both immature and mature thymocytes expressed a similar profile of PLC isoenzyme mRNA species, indicating that the defect in signaling in immature thymocytes was not due to altered expression of PLC isoenzymes. Activation of tyrosine phosphorylation pathways implicated in the coupling of TCR/CD3 to PLC was impaired in immature thymocytes, as evidenced by depressed phosphorylation of CD3 zeta subunit after stimulation with anti TCR/CD3 mAb. This was associated with lower levels of p59fyn tyrosine kinase and minimal or undetectable stimulus-induced kinase activation in immature thymocytes relative to mature thymocytes. We conclude that the capacity to signal via TCR/CD3 is regulated during T cell development by mechanisms acting at the level of TCR/CD3-associated tyrosine phosphorylation pathways.

Developmental regulation of transmembrane signaling via the T cell antigen receptor/CD3 complex in human T lymphocytes

We have examined transmembrane signaling events via the TCR/CD3 complex (TCR/CD3) at various stages of T cell development for evidence of developmental regulation. Engagement of TCR/CD3 induced defective activation of phospholipase C (PLC) in thymocytes relative to peripheral blood T lymphocytes. The defect in PLC activation via TCR/CD3 was restricted to immature thymocytes (CD3low, CD4+CD8+). Mature thymocytes (CD3high, CD4+CD8-/CD8+CD4-) were similar to PBL in signaling via TCR/CD3. Both immature and mature thymocytes expressed a similar profile of PLC isoenzyme mRNA species, indicating that the defect in signaling in immature thymocytes was not due to altered expression of PLC isoenzymes. Activation of tyrosine phosphorylation pathways implicated in the coupling of TCR/CD3 to PLC was impaired in immature thymocytes, as evidenced by depressed phosphorylation of CD3 zeta subunit after stimulation with anti TCR/CD3 mAb. This was associated with lower levels of p59fyn tyrosine kinase and minimal or undetectable stimulus-induced kinase activation in immature thymocytes relative to mature thymocytes. We conclude that the capacity to signal via TCR/CD3 is regulated during T cell development by mechanisms acting at the level of TCR/CD3-associated tyrosine phosphorylation pathways.

Novel immune deficiencies: defective transcription of lymphokine genes

A 4-year-old female with severe combined immunodeficiency (SCID) had normal numbers of T cells in circulation and normal T cell subsets. However, her T cells proliferated poorly to mitogens and did not proliferate to antigens or to anti-CD3 mAb. Interleukin-2 (IL-2) receptor expression was normal but IL-2 synthesis was undetectable. The addition of recombinant IL-2 to a mitogen-stimulated culture resulted in normalization of the proliferative response. Northern blot analysis of total RNA derived from the patient's T cells revealed a weak or absent expression of mRNA coding for IL-2, IL-3, IL-4, and IL-5. In contrast, there were normal amounts of mRNA coding for granulocyte-macrophage colony-stimulating factor (GM-CSF). Tumor necrosis factor and IL-6 production was also normal. Nuclear run on transcriptional assays revealed markedly decreased levels of newly initiated nuclear transcripts coding for IL-2, IL-3, IL-4, and IL-5 and normal levels of GM-CSF transcripts in patient relative to control lymphocytes. These results indicate that the patient's T cells suffered from a defect affecting the transcription of multiple T cell lymphokines and suggest that abnormalities affecting the production of T cell lymphokines may underlie some of the primary immunodeficiency diseases.

Immunosuppressive activity of 13-cis-retinoic acid and prevention of experimental autoimmune encephalomyelitis in rats

Some activities of retinoids on cellular and humoral immunity have been described, but the available data are conflicting or obtained at concentrations that are toxic in vivo. In this study, we demonstrate that 13-cis-retinoic acid (13-cRA), a retinoid well tolerated in human therapy, can suppress T cell-mediated immunity in rats. Treatment with pharmacological concentrations of 13-cRA prevented active as well as passive transfer experimental autoimmune encephalomyelitis (EAE) and suppressed lymphocyte responsiveness to T cell mitogens, suggesting that the drug activity included suppression of an effector T cell response. In addition, mitogen- and antigen-induced lymphocyte proliferation was inhibited in vitro in the presence of concentrations of 13-cRA equivalent to or less than those achieved in vivo, further suggesting that the prevention of EAE was due to a suppressive activity on T cell-mediated immunity. The immunosuppressive activity of 13-cRA included suppression of interleukin 2, whose production was inhibited in splenocytes. These data indicate that, in an in vivo mammalian system, 13-cRA exerts a suppressive activity on T cell-mediated immunity intensive enough to suppress an ongoing immune response, and that this effect can be achieved at nontoxic concentrations that may also be attained in human therapy.

Active polysomes in the axoplasm of the squid giant axon

Axons and axon terminals are widely believed to lack the capacity to synthesize proteins, relying instead on the delivery of proteins made in the perikaryon. In agreement with this view, axoplasmic proteins synthesized by the isolated giant axon of the squid are believed to derive entirely from periaxonal glial cells. However, squid axoplasm is known to contain the requisite components of an extra-mitochondrial protein synthetic system, including protein factors, tRNAs, rRNAs, and a heterogeneous family of mRNAs. Hence, the giant axon could, in principle, maintain an endogenous protein synthetic capacity. Here, we report that the squid giant axon also contains active polysomes and mRNA, which hybridizes to a riboprobe encoding murine neurofilament protein. Taken together, these findings provide direct evidence that proteins (including the putative neuron-specific neurofilament protein) are also synthesized de novo in the axonal compartment.

Primary combined immunodeficiency resulting from defective transcription of multiple T-cell lymphokine genes

The circulating T lymphocytes of a female child with recurrent opportunistic infections were normal in number and phenotype but exhibited poor proliferation and decreased synthesis of the T-cell growth factor interleukin (IL) 2 in response to mitogens. Recombinant IL-2 fully restored the proliferative responses of her T cells, suggesting that her poor immune function was related to IL-2 deficiency. Northern blot analysis of total cellular RNA from the patient's T cells revealed markedly decreased levels of IL-2 mRNA of normal size. In addition, mRNA levels of other lymphokines selectively expressed by T cells, which include IL-3, IL-4, and IL-5, were either severely depressed or absent. The levels of interferon gamma mRNA were moderately decreased, while those of granulocyte-macrophage colony stimulating factor, a lymphokine the production of which is not restricted to T cells, were unaffected. The decreased level of lymphokine mRNA in the patient's T lymphocytes was not from enhanced catabolism but resulted from a diminution in the transcription rate of the affected lymphokine genes. Normal transduction via the T-cell receptor/CD3 complex of biochemical signals necessary for the initiation of lymphokine gene transcription indicated that the defect was distal to the membrane signal-transducing apparatus. The defect is hypothesized to involve a T-cell-specific trans-acting regulatory factor required for transcription of the affected lymphokine genes.

Circadian oscillations of DNA synthesis in rat brain

The possibility that the synthesis of brain DNA undergoes a circadian fluctuation was examined in male adult Wistar rats, kept under natural lighting conditions or born and raised under artificial lighting conditions. Groups of rats were taken every 4 h during the 24 h, injected subcutaneously with [methyl-3H]thymidine and killed 4 h later. By cosinor analysis, the DNA specific activity of cerebral hemispheres and brainstem was found to show a significant 24 h rhythm with the peak at the beginning of the dark period (waking period). By contrast, in kidney, the peak of the circadian rhythm of DNA specific activity occurred during the light period (sleep period), in agreement with literature data. On the other hand, in 4-week-old rats, born and raised in artificial lighting conditions, brain DNA specific activity followed a 12 h rhythm, in agreement with the lack of a significant diurnal oscillation of the sleep--waking structure. It is concluded that brain DNA synthesis undergoes a circadian fluctuation in association with the circadian rhythm of waking.

Occurrence and sequence complexity of polyadenylated RNA in squid axoplasm

Axoplasmic RNA from the giant axon of the squid (Loligo pealii) comprises polyadenylated [poly (A)+] RNA, as judged, in part, by hybridization to [3H]polyuridine and by in situ hybridization analyses using the same probe. The polyadenylate content of axoplasm (0.24 ng/microgram of total RNA) suggests that the poly(A)+ RNA population makes up approximately 0.4% of total axoplasmic RNA. Axoplasmic poly(A)+ RNA can serve as a template for the synthesis of cDNA using a reverse transcriptase and oligo(deoxythymidine) as primer. The size of the cDNA synthesized is heterogeneous, with most fragments greater than 450 nucleotides. The hybridization of axoplasmic cDNA to its template RNA reveals two major kinetic classes: a rapidly hybridizing component (abundant sequences) and a slower-reacting component (moderately abundant and rare sequences). The latter component accounts for approximately 56% of the total cDNA mass. The rapidly and slowly hybridizing kinetic components have a sequence complexity of approximately 2.7 kilobases and 3.1 X 10(2) kilobases, respectively. The diversity of the abundant and rare RNA classes is sufficient to code for one to two and 205, respectively, different poly(A)+ RNAs averaging 1,500 nucleotides in length. Overall, the sequence complexity of axoplasmic poly(A)+ RNA represents approximately 0.4% that of poly(A)+ mRNA of the optic lobe, a complex neural tissue used as a standard. Taken together, these findings indicate that the squid giant axon contains a heterogeneous population of poly(A)+ RNAs.

Presence of activated T-cells with a T8+ M1+ Leu 7+ surface phenotype in invaded lymph nodes from patients with solid tumors

The lymphocyte surface phenotype of lymph nodes from patients with larynx or urinary bladder carcinoma was investigated by using a panel of monoclonal antibodies. The phenotype pattern of lymphocytes from lymph nodes invaded by malignant cells (as assessed by histopathology) was different from that of the cells from noninvaded or normal control nodes. Although the proportion of natural killer cells or macrophages was similar in the 3 groups of lymph nodes, invaded lymph nodes contained a higher proportion of T-cells and a lower B-cell percentage. Furthermore, cells from invaded nodes comprised 15-20% of T3+ T8+ cells that coexpressed the M1 marker and, to some extent, also the Leu 7 marker. A large proportion of cells with multiple markers were activated, as shown by the expression of Tac and HLA-DR antigens. In 2 patients activated T8+ cells expressing also M1 and Leu 7 markers infiltrated the tumor site. The presence of these activated cells both in involved nodes and tumor mass may indicate that they originate in response to cancer.

Paradoxical sleep deprivation of the mother enhances DNA synthesis in fetal rat brain: autoradiographic and biochemical evidence

Pregnant rats were deprived of paradoxical sleep for 3 days starting on the 18th gestational day. The condition of PS-D was imposed by confinement on a small platform surrounded by water or by daily injections of clomipramine. Four hours before the killing rats received a s.c. injection of [3H]-thymidine. The amount of radioactive DNA determined by autoradiography in several regions of fetal brain was found to be markedly increased under both experimental conditions in comparison with the control fetal brain. Considerably more limited effects were observed in kidney. Comparable changes of lower magnitude were obtained by comparing the specific radioactivity of DNA samples purified by chlorophorm extraction and digestion with RNase and proteinase K. The results fully confirm our previous data obtained under similar experimental conditions but based on the analysis of an acid-washed DNA fraction.

Production of B cell growth factor by a Leu-7+, OKM1+ non-T cell with the features of large granular lymphocytes (LGL)

The present study reports the characterization of a non-T cell from human peripheral blood which is capable of releasing BCGF. This BCGF-producing non-T cell had a T3-, T8-, Leu-7+, OKM1+, HLA-DR-, Leu-11- surface phenotype and was likely to belong to the so-called large granular lymphocyte (LGL) subset because: after fractionation of non-T cells according to the expression of Leu-7 or HLA-DR markers, it was found in the Leu-7+, HLA-DR- fractions that were particularly enriched in LGL; it co-purified with LGL on Percoll density gradients; and it expressed Leu-7 and OKM1 markers that are shared by a large fraction of LGL. Although co-purified with cells with potent NK capacities, the BCGF-producing cell was not cytotoxic, because treatment of Leu-7+ cells with Leu-11 monoclonal antibody and complement abolished the NK activity but left the BCGF activity unaltered. The factor released by this LGL subset was not IL 1 or IL 2 mistakenly interpreted as BCGF, because: a) cell supernatants particularly rich in BCGF activity contained very little or no IL 1 or IL 2; b) BCGF-induced B cell proliferation was not inhibitable by anti-Tac antibodies (this in spite of the expression of IL 2 receptor by a proportion of activated B cells); and c) BCGF activity was absorbed by B but not T blasts.

Production of B cell growth factor by a Leu-7+, OKM1+ non-T cell with the features of large granular lymphocytes (LGL)

The present study reports the characterization of a non-T cell from human peripheral blood which is capable of releasing BCGF. This BCGF-producing non-T cell had a T3-, T8-, Leu-7+, OKM1+, HLA-DR-, Leu-11- surface phenotype and was likely to belong to the so-called large granular lymphocyte (LGL) subset because: after fractionation of non-T cells according to the expression of Leu-7 or HLA-DR markers, it was found in the Leu-7+, HLA-DR- fractions that were particularly enriched in LGL; it co-purified with LGL on Percoll density gradients; and it expressed Leu-7 and OKM1 markers that are shared by a large fraction of LGL. Although co-purified with cells with potent NK capacities, the BCGF-producing cell was not cytotoxic, because treatment of Leu-7+ cells with Leu-11 monoclonal antibody and complement abolished the NK activity but left the BCGF activity unaltered. The factor released by this LGL subset was not IL 1 or IL 2 mistakenly interpreted as BCGF, because: a) cell supernatants particularly rich in BCGF activity contained very little or no IL 1 or IL 2; b) BCGF-induced B cell proliferation was not inhibitable by anti-Tac antibodies (this in spite of the expression of IL 2 receptor by a proportion of activated B cells); and c) BCGF activity was absorbed by B but not T blasts.

Activation of phosphatidylserine synthesis: a possible mechanism of regulation of the base-exchange enzymic system

The possible relationship between phosphatidyl serine synthesis by base-exchange and nervous activity has been investigated in the rat caudate nucleus. The rate of incorporation of L-serine into the phosphatidyl serine of slices from caudate nucleus is not affected by dopamine nor is it affected by the addition to dopamine of a cyclic phosphodiesterase inhibitor which would increase the endogenous cyclic-AMP levels. However, imidazole, a phosphodiesterase activator, clearly stimulates by more than 100% the phosphatidyl serine synthesis in the slices. The activation is not due to interaction at the catalytic site(s) of the base-exchange system, since it is neither observed in homogenates of caudate nucleus nor in cerebral microsomes at various pH values.

[Preliminary data on the behavior of the enzyme of metabolism of phospholipid bases in human tumor preparations]

The A.A. have investigated the phospholipids base-exchange enzyme system in the solid tumours in order to state if a correlation between this activity and the variation of the cellular ciclic nucleotides amount was possible considering that these compounds have been reported to undergo a variation in tumour compared with normal tissues. They report some previous results in a lung tumour and in an endometrial carcinoma, were they have found a big increase in the PhS synthesis. Such increase was possible to be seen in the endometrial carcinoma only after a stimulation by 17-beta-estradiol and it was reversed in this case by doxorubicine. These results suggest that an alteration of the PhS synthesis should be one of numerous peculiarity of the neoplastic cell.

[Preliminary data on activation of the enzyme of the metabolism of phospholipid bases in various areas of the brain]

The scope of this work was to study the effect of imydazole on base-exchange enzymic system in selected cerebral areas. We have previously demonstrated that imydazole was an activator of phosphatidylserine synthesis in slices of caudate nucleus. This effect lacked in the omogenate we had supposed that this activation by imydazole was not directed on base-exchange enzymic system, but was induced by decrease of cellular cyclic nucleotides amount. Therefore we have investigated the effect of dibutirril-AMPciclic in selected cerebral areas. In addition it was useful to state if activation by imydazole was area-specific or not.

[Changes in phosphatidylserine synthesis in human rectal tumors]

We have investigated the phosphatidylserine metabolism in human adenocarcinoma. This phospholipid is involved in the regulation of several enzymic activities of plasma membranes; therefore it could be useful to state if some alteration of tumour membranes propriety depend on variation of phosphatidylserine synthesis. Our results make evident that in such human tumours the phosphatidylserine synthesis is greatly augmented.

Late appearance of an IgA (kappa) monoclonal protein in a patient with IgG (kappa) multiple myeloma: sharing of idiotypic specificities between the two serum proteins

A patient with an IgG(chi) monoclonal serum protein developed in the course of the disease a second monoclonal spike of the same light chain type and of the IgA class. The latter monoclonal protein progressively increased and eventually exceeded the first IgG(chi) protein. Antigenic analysis of the two myeloma proteins demonstrated that they shared idiotypic determinants. Immunofluorescence studies, carried out with anti gamma and anti alpha reagents tagged with different fluorochromes revealed that the two isotypes were produced by different plasma cells. The data are discussed in the prospect of a possible transitional mechanism from IgG to IgA synthesis within a single B cell clone.

The effect of silybin on liver phospholipid synthesis in the rat in vivo

Female Wistar rats have been injected intravenously for seven days with various different doses of silybin, the main component of the drug silymarin, and the in vitro synthesis of phosphatidylethanolamine and phosphatidylcholine from their respective precursors, CDP-ethanolamine and CDP-choline has been examined in liver microsomal membranes. Appreciable inhibition of the incorporation rates of precursors into lipids has been noticed at dosage of 15-20 mg/100 g body wt., daily. No evident effect is exerted by similar silybin treatment on choline and ethanolamine incorporation respectively into liver phosphatidylcholine and phosphatidylethanolamine in vivo.

[Lysosomal lesions during a course of acute experimental muscular ischemia. Protective effect of a polypetitide proteinase inhibitor]

Three groups of rabbits were used: a) with acute ischaemia in a rear limb; b) with acute ischaemia in a rear limb and treated with i.v. 100,000 KIU of a proteinase-inhibitor polypeptide extracted from ox lung; c) normal controls. Acute ischaemia was obtained by ligature of the ipsilateral common iliac, external iliac, inferior epigastric and femoral arteries. Soluble and total activity of 3 lysosomal enzymes (cathepsin, acid phosphatase and N-acetyl-glucosaminidase) were determined in gastrocnemius muscle from all 3 groups. The mean ratio between bound and soluble activity for all 3 enzymes in normal gastrocnemius muscle was higher than in ischaemic muscle, but not significantly different from that in ischemic muscle of animals treated with the polypeptide. Furthermore, this ratio in ischemic muscle was significantly lower than that of ischemic muscle of the rabbits treated with the polypeptide. These data suggest that the polypeptide offers protection against lysosomal lesion in the course of experimental ischaemia of the skeletal muscle.

Changes in enzyme levels in human skeletal muscle during obstructive arteriopathy of the lower limbs

Some enzymatic activities have been assayed in the gastrocnemius muscle of patients with obstructive arteriopathy of the lower limbs. The specific activities of all the examined glycolytic enzymes, of malate dehydrogenase and of glycerol-3-phosphate dehydrogenase are significantly decreased while the specific activities of two lysosomal enzymes, beta-glucuronidase and cathepsin A, are significantly higher than in the controls. Therefore it may be inferred that the metabolic capacity of glycolysis and of Krebs cycle are lowered. On the other hand the increased specific activity of lysosomal enzymes suggests the hypothesis that the above mentioned modifications and the morphologic alterations of the muscle and of the small blood vessels might be ascribed, at least partly, to a release of lysosomal hydrolases in active form.