Changes in physical activity among coronary and hypertensive patients: A longitudinal study using the Health Action Process Approach.

OBJECTIVES: Physical activity (PA) is a key factor in cardiovascular disease prevention. Through the Health Action Process Approach (HAPA), the present study investigated the process of change in PA in coronary patients (CPs) and hypertensive patients (HPs). DESIGN: Longitudinal survey study with two follow-up assessments at 6 and 12 months on 188 CPs and 169 HPs. MAIN OUTCOME MEASURES: Intensity and frequency of PA. RESULTS: A multi-sample analysis indicated the equivalence of almost all the HAPA social cognitive patterns for both patient populations. A latent growth curve model showed strong interrelations among intercepts and slopes of PA, planning and maintenance self-efficacy, but change in planning was not associated with change in PA. Moreover, increase in PA was associated with the value of planning and maintenance self-efficacy reached at the last follow-up Conclusions: These findings shed light on mechanisms often neglected by the HAPA literature, suggesting reciprocal relationships between PA and its predictors that could define a plausible virtuous circle within the HAPA volitional phase. Moreover, the HAPA social cognitive patterns are essentially identical for patients who had a coronary event (i.e. CPs) and individuals who are at high risk for a coronary event (i.e. HPs).

Predicting depression from illness severity in cardiovascular disease patients: self-efficacy beliefs, illness perception, and perceived social support as mediators.

BACKGROUND: Many studies have investigated the relationships between cardiovascular diseases and patients' depression; nevertheless, few is still known as regard the impact of illness severity on depression and whether psychosocial variables mediate this association. PURPOSE: The aim of this study is to investigate the putative mediating role of illness representations, self-efficacy beliefs, and perceived social support on the relationship between illness severity and depression. METHODS: A total of 75 consecutive patients with cardiovascular disease (80 % men; mean age = 65.44, SD = 10.20) were enrolled in an Italian hospital. Illness severity was measured in terms of left ventricular ejection fraction, whereas psychological factors were assessed using self-report questionnaires. RESULTS: The relationship between left ventricular ejection fraction and depression was mediated by identity illness perception, self-efficacy beliefs in managing cardiac risk factors, and perceived social support. CONCLUSION: The treatment of depression in cardiovascular disease patients may therefore benefit from a psychological intervention focused on patients' illness representations, self-efficacy beliefs, and their perceived social support.

A psychometric evaluation of the Group Environment Questionnaire in a sample of professional basketball and soccer players.

Psychometric properties of the Group Environment Questionnaire were investigated in a large sample of soccer (n = 222) and professional basketball players (n = 375). Confirmatory factor analysis was performed both on the total sample and on the two subsamples through a multi-group approach; associations between cohesion and the duration of belonging to the team were also explored. Results confirmed the four-factor structure proposed by Carron's original model even though some items with low loadings were eliminated. No significant associations were found between team cohesion and the duration of belonging to the team.

[Pain assessment in terminally-ill cancer patients on admission in hospice and its modification after the first three days of care. A monocentric experience]. / Il dolore nel paziente oncologico terminale: valutazione del sintomo all'ingresso in hospice e delle sue modifi cazioni nei primi tre giorni di assistenza. Esperienza monocentrica.

AIMS: Pain is among the most frequent and distressing symptoms in terminally-ill cancer and, to date, many patients still experience uncontrolled pain. In this paper we evaluated prevalence and intensity of pain on admission in our palliative care center and during the first three days of care. PATIENTS AND METHODS: From September 2009 to October 2009 we consecutively recruited 96 terminally-ill cancer patients : on admission more than 50% had severe pain and only 4% referred to be pain-free. 54% of patients was on treatment with strong opioids. RESULTS: After three days from admission in our palliative care unit only 7% of patients experienced severe pain, 25% reported absence of pain and 80% of patients was on treatment with strong opioids. CONCLUSIONS: The beginning of palliative care led to a meaningful and rapid reduction of pain in the vast majority of terminally-ill cancer patients evaluated in this study.

Inhibition of osteogenesis in vitro by a cigarette smoke-associated hydrocarbon combined with Porphyromonas gingivalis lipopolysaccharide: reversal by resveratrol.

BACKGROUND: Smoking and infection with Gram-negative bacterial pathogens are risk factors for alveolar bone loss. The aims of this study were: 1) to examine the combined effects of an aryl hydrocarbon, benzo[a]pyrene (BaP), that is concentrated in cigarette smoke, and lipopolysaccharide (LPS) extracted from Porphyromonas gingivalis on osteogenesis in a rat bone marrow cell (RBMC) model of osteogenesis; and 2) to determine whether resveratrol (Res), an aryl hydrocarbon receptor antagonist, could reverse the putative inhibitory effects of BaP + LPS on osteogenesis. METHODS: LPS of P. gingivalis strain 2561 was introduced in various concentrations to the RBMC in 96-well plates and kept in culture for 8 to 12 days. The same protocol was used for studying BaP and LPS + BaP combinations. Following the incubation periods, parameters of osteogenesis were measured, including formation of mineralized bone nodules, alkaline phosphatase activity, and total cell protein. Transcription of the pro-inflammatory cytokine interleukin (IL)-1beta in the cultures was determined by reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Bone nodule formation generally decreased significantly with increasing LPS concentrations (P<0.05), whereas total cell protein decreased only slightly (P>0.05). BaP in previously high concentrations alone also caused a significant dose-dependent decrease in bone nodule formation (P<0.05) but when half maximal doses were used, significant decreases were most often seen when LPS was added. Hence, in combination, the inhibitory effects of LPS + BaP on osteogenesis were additive, inhibiting bone nodule formation up to 9-fold. Resveratrol partially reversed the inhibitory effects of low concentrations of LPS alone, and completely reversed the inhibition of nodule formation when low concentrations of LPS were combined with BaP. IL-1beta expression generally fluctuated inversely to the inhibitory activity of LPS, LPS + BaP, and LPS + BaP + Res combinations. CONCLUSIONS: Smoke-derived aryl hydrocarbons and bacterial LPS may act additively to inhibit bone formation. The findings may explain, in part, why net periodontal bone loss is greater and bone healing is less successful in smokers than non-smokers with periodontal infections. Reversal of the inhibitory effects in vitro by resveratrol suggests that this phytoalexin should be studied further for its potential therapeutic value, given its aryl hydrocarbon receptor antagonism and apparent anti-inflammatory activity.

Cytoprotection against mechanical forces delivered through beta 1 integrins requires induction of filamin A.

Cells in mechanically active environments can activate cytoprotective mechanisms to maintain membrane integrity in the face of potentially lethal applied forces. Cytoprotection may be mediated by expression of membrane-associated cytoskeletal proteins including filamin A, an actin-binding protein that increases the rigidity of the subcortical actin cytoskeleton. In this study, we tested the hypotheses that applied forces induce the expression of filamin A specifically and that this putative protective response inhibits cell death. Magnetically generated forces were applied to protein-coated magnetite beads bound to human gingival fibroblasts, cells with constitutively low basal levels of filamin A mRNA and protein. Forces applied through collagen or fibronectin, but not bovine serum albumin or poly-l-lysine-coated beads, increased mRNA and protein content of filamin A by 3-7-fold. Forces had no effect on the expression of other filamin isotypes or other cytoskeletal proteins. This effect was dependent on the duration of force and was blocked by anti-beta(1) integrin antibodies. Force also stimulated a 60% increase in expression of luciferase under the control of a filamin A promoter in transiently transfected Rat2 fibroblasts and was dependent on Sp1 transcription factor binding sites located immediately upstream of the transcription start site. Experiments with actinomycin D-treated cells showed that the increased filamin A expression after force application was due in part to prolongation of mRNA half-life. Antisense filamin oligonucleotides blocked force-induced filamin A expression and increased cell death by >2-fold above controls. The force-induced regulation of filamin A was dependent on intact actin filaments. We conclude that cells from mechanically active environments can couple diverse signals from forces applied through beta-integrins to up-regulate the production of cytoprotective cytoskeletal proteins, typified by filamin A.

Epstein-Barr Virus and its glycoprotein-350 upregulate IL-6 in human B-lymphocytes via CD21, involving activation of NF-kappaB and different signaling pathways.

Epstein-Barr virus (EBV) is a ubiquitous and highly immunotropic gamma herpesvirus that infects more than 90 % of humans worldwide. Its pathogenicity leads to a number of diseases including tumors that result from EBV's ability to readily transform B-lymphocytes and, to a lesser extent, epithelial cells. EBV utilizes CD21/CR2 as its receptor on B cells to initiate the infection process. EBV binds to CR2 through its major envelope glycoprotein-350 (gp350) and is also a remarkable immunomodulating agent. We had previously shown that EBV is capable of modulating the synthesis of a number of cytokines. We now show that while both purified recombinant gp350 (rgp350) and EBV upregulate IL-6 mRNA synthesis in B cells, EBV-induced IL-6 gene activation occurs for a significantly longer period of time (i.e. 12 hours for EBV as compared to 6 hours for rgp350). Moreover, the half-life of EBV-induced IL-6 mRNA was also significantly longer (10 hours) than that of mRNA induced by rgp350 (about 6 hours). Both EBV and gp350 enhance the binding of the NF-kappaB transcription factor, as determined by band-shift and augment NF-kappaB-mediated activation of a CAT reporter plasmid. Furthermore, we demonstrate that while the activation of IL-6 gene expression by gp350 is mediated primarily by the protein kinase C pathway, EBV can mediate its effects through multiple signaling pathways. To our knowledge this is the first report showing that the binding of a herpesvirus envelope glycoprotein to CR2 on human B cells results in the activation of the NF-kappaB transcription factor leading to the upregulation of IL-6 gene expression in these lymphocytes.

Ethnic differences in the expression of Epstein-Barr virus latent membrane protein-1 mutations in nasopharyngeal carcinoma.

The latent membrane protein-1 (LMP1) of Epstein-Barr virus (EBV) is a viral oncoprotein implicated in several EBV-associated pathologies. Many studies have characterized carboxy-terminal mutations within LMP1, errors in this area are critical since this portion contains sequences responsible for LMP1 targeting, half-life and association with host cell proteins. Although, data suggests that mutations in this area extend LMP1 half-life and increase its oncogenesis, some studies have not shown this to be true for all EBV-associated tumors. In order to evaluate 3'-end LMP1-DNA mutations in three different ethnic populations with nasopharyngeal carcinoma (NPC), we examined EBV-DNA in 34 patients of various origins (Caucasian, Chinese and Inuit). While 68% of the total group expressed EBV-antigens, only 56% of Caucasians but 86% of Inuit expressed this viral protein. Over 67% of Inuit NPC tissue contained the characteristic 30 bp deletion that was observed in only 20% of Caucasians and 33% of Chinese samples. DNA sequencing revealed that the Inuit population showed the most frequent DNA mutations and corresponding amino acid alterations in LMP1. Our results suggest that EBV-associated NPC-DNA mutations in LMP1 do not occur at equal rates in different racial groups and are more common at distinct sites in NPC tissue from Chinese and Inuit sources.

Binding of the Epstein-Barr virus major envelope glycoprotein gp350 results in the upregulation of the TNF-alpha gene expression in monocytic cells via NF-kappaB involving PKC, PI3-K and tyrosine kinases.

Epstein-Barr virus (EBV) is a human herpesvirus that interacts with various immunocompetent cells that carry the EBV receptor (CD21/CR2). EBV binds to CR2 through its major envelope glycoprotein 350 (gp350). Previously we had demonstrated that EBV and other human herpesviruses are capable of modulating cytokine synthesis through the deregulated expression of cytokine genes interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and interleukin-2 (IL-2). Here we show that, in contrast to infectious EBV, purified recombinant gp350 upregulates TNF-alpha gene expression in human monocyte/macrophages (M/M) as well as in a monocytoid cell line, U937. Our results also demonstrate that this increased expression is due to both enhanced transcription and stability of TNF-alpha mRNA in gp350-treated cells. The specificity of this effect is evidenced by the fact that pre-incubation of cells with anti-CR2 monoclonal antibody OKB7, which blocks binding of gp350 to CR2, inhibits the above mentioned effects of gp350. Furthermore, we demonstrate that activation of TNF-alpha by gp350 is mediated by NF-kappaB through signal transduction pathways involving PKC, PI3-K and tyrosine kinases. To our knowledge this is the first report describing the modulation of TNF-alpha gene expression by the EBV-gp350 molecule following its interaction with the viral receptor CR2 on cells of the monocytic lineage.

Analysis and significance of anti-latent membrane protein-1 antibodies in the sera of patients with EBV-associated diseases.

Anti-latent membrane protein-1 (LMP-1) is an EBV-encoded type III integral membrane protein with oncogenic potential that is expressed most consistently in various EBV-associated malignancies. Unlike many other EBV proteins, LMP-1 Abs have rarely been demonstrated in EBV-associated disease conditions. We established a high level LMP-1-expressing cell clone and used it for the detection, quantitation, and characterization of these Abs in various human sera in immunoblots and ELISA. Our results demonstrate that, in contrast to the commonly held notion, LMP-1 induces significant humoral immune responses in EBV-associated malignant conditions especially in nasopharyngeal carcinoma (NPC) patients in whom >70% sera are positive for these Abs, and their titers correlate with the clinical condition of the tumors. Interestingly, anti-LMP-1 Abs of IgA isotype were found only in NPC patients. These Abs were absent from the sera of infectious mononucleosis and chronic EBV infection patients, whereas a small fraction ( approximately 5%) of the healthy, EBV-seropositive individuals were positive for them; however, their OD values were much lower than those of NPC patients. These studies demonstrate, for the first time, the potential significance of LMP-1-specific Abs for the diagnosis and prognosis of EBV-associated malignancies, especially of NPC.

Epstein-Barr virus envelope glycoprotein gp350 induces NF-kappaB activation and IL-1beta synthesis in human monocytes-macrophages involving PKC and PI3-K.

Epstein-Barr virus (EBV) is a highly immunotropic human herpesvirus with oncogenic potential and is involved in numerous pathologies. EBV utilizes its major envelope glycoprotein gp350 to bind to its receptor CR2/CD21 on target cells for initiating the infection. We have previously shown that EBV is able to modulate transcription and translation of a number of cytokine genes via its gp350-mediated binding to this receptor. However, the effects of the binding of purified gp350 to CR2/CD21 on plastic-adherent monocyte-macrophages (AMM) have not been investigated. These cells are a rich source of potent proinflammatory and immune-modulating cytokines, and express low levels of CR2/CD21. We show here for the first time that recombinant gp350 (rgp350) causes production of the potent proinflammatory cytokine IL-1beta in human AMM. Surprisingly, rgp350 is comparable in this capacity to the phorbol ester 12-0-tetradecanoylphorbol 13-acetate. This induction of IL-1beta production was accompanied by increased steady-state levels of its mRNA in gp350-treated AMM, and was dependent on the specific binding of rgp350 to the EBV receptor CR2/CD21. We also show that the signaling pathways resulting in the induction of IL-1beta synthesis by rgp350 required protein kinase C and phosphatidylinositol 3,4,5 triphosphate kinase activities and occurred via activation of the NF-kappaB family of transcription factors.-D'Addario, M., Ahmad, A., Xu, J. W., Menezes, J. Epstein-Barr virus envelope glycoprotein gp350 induces NF-kappaB activation and IL-1beta synthesis in human monocytes-macrophages involving PKC and PI3-K.

Modulatory effects of human herpes virus-7 on cytokine synthesis and cell proliferation in human peripheral blood mononuclear cell cultures.

Human herpes virus-7 (HHV-7) infects cells of the immune system and thus may modulate their function. To investigate the potential immunomodulatory effects of this virus, we performed an in vitro study in which we investigated effects of HHV-7 on the synthesis of several key immunomodulatory cytokines, i.e. tumor necrosis factor alpha (TNF-alpha), interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-4, IL-6, and transforming growth factor beta (TGF-beta). This was examined after in vitro infection of human peripheral blood mononuclear cells (PBMC) with HHV-7. We found elevated levels of TNF-alpha, TGF-beta, and IFN-gamma in the supernatants of HHV-7-infected cells. By reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, using cytokine-specific primers, we found that levels of TNF-alpha, TGF-beta, and IFN-gamma mRNA were increased in the infected cells. The HHV-7 infection also significantly (P < 0.05) decreased the production of IL-2 from activated, IL-2-producing PBMC. Furthermore, mitogen- and cytokine-induced cellular proliferative responses of human PBMC were found to be significantly (P < 0.05) down-regulated by this virus. On the other hand, HHV-7 did not affect IL-4 and IL-6 synthesis. Overall, our results indicate that HHV-7 infection causes significant immunomodulatory effects with regard to cytokine synthesis in these cells as well as inhibiting lymphocyte proliferation by various stimuli.

The Epstein-Barr virus (EBV) major envelope glycoprotein gp350/220-specific antibody reactivities in the sera of patients with different EBV-associated diseases.

gp350 of Epstein-Barr virus (EBV) induces a strong immune response in EBV-infected individuals, but relatively little is known about the clinical relevance of this response in patients with different EBV-associated malignancies and other diseases. Using our gp350-expressing cell clones, we studied gp350-specific humoral immune responses in the sera of individuals with nasopharyngeal carcinoma (NPC), chronic symptomatic EBV infection (CEI), Hodgkin's disease (HD), acute infectious mononucleosis (IM) and healthy EBV-seropositive individuals (HI). The titres of antibody-dependent cellular cytotoxicity (ADCC) antibodies were highest in HI followed by CEI, HD and NPC. EBV-neutralizing (NA) and gp350-specific IgG antibody profiles in these conditions were: CEI > HI > NPC > HD, whereas IgA titres were the highest in NPC sera followed by CEI and HD. The sera from IM patients were found to be negative for gp350-specific ADCC and IgA activities. Sera from HI were also negative for gp350-specific IgA. A significant positive correlation was found between serum gp350 IgA and viral capsid antigen IgA and a significant negative one between IgM and ADCC titres. High IgA titres were also found in CEI and EBV-genome positive HD in addition to NPC. Importantly, gp350-specific IgA titres were of prognostic value in NPC patients. Our data provide new insights about the clinical relevance of gp350-specific immune responses in these diseases.

Characterization of a functional NF-kappa B site in the human interleukin 1 beta promoter: evidence for a positive autoregulatory loop.

The -300 region of the interleukin 1 beta (IL-1 beta) promoter contains a functional NF-kappa B binding site composed of the decamer sequence 5'-GGGAAAATCC-3'. Probes representing the -300 region or the NF-kappa B site alone interacted with NF-kappa B proteins present in phorbol myristate acetate-, lipopolysaccharide-, or Sendai virus-induced myeloid cell extracts as well as recombinant NFKB1 (p50) and RelA (p65); furthermore, NF-kappa B protein-DNA complex formation was dissociated in vitro by the addition of recombinant I kappa B alpha. Mutation of the NF-kappa B site in the context of the IL-1 beta promoter reduced the responsiveness of the IL-1 beta promoter to various inducers, including phorbol ester, Sendai virus, poly(rI-rC), and IL-1 beta. A 4.4-kb IL-1 beta promoter fragment linked to a chloramphenicol acetyltransferase reporter gene was also preferentially inducible by coexpression of individual NF-kappa B subunits compared with a mutated IL-1 beta promoter fragment. When multiple copies of the IL-1 beta NF-kappa B site were linked to an enhancerless simian virus 40 promoter, this element was able to mediate phorbol ester- or lipopolysaccharide-inducible gene expression. In cotransfection experiments, RelA (p65) and c-Rel (p85) were identified as the main subunits responsible for the activation of the IL-1 beta NF-kappa B site; also, combinations of NFKB1 (p50) and RelA (p65) or c-Rel and RelA were strong transcriptional activators of reporter gene activity. The presence of a functional NF-kappa B binding site in the IL-1 beta promoter suggests that IL-1 positively autoregulates its own synthesis, since IL-1 is a strong inducer of NF-kappa B binding activity. Thus, the IL-1 beta gene may be considered as an important additional member of the family of cytokine genes regulated in part by the NF-kappa B/rel family of transcription factors.

Modulatory effects of Epstein-Barr, herpes simplex, and human herpes-6 viral infections and coinfections on cytokine synthesis. A comparative study.

Herpesviruses such as EBV, HSV, and human herpes virus-6 (HHV-6) have a marked tropism for cells of the immune system and therefore infection by these viruses may result in alterations of immune functions, leading at times to a state of immunosuppression. We report the results of a comparative study in which we found that EBV, HSV-1, and HHV-6 act differentially on the immune system with regard to their effect on the synthesis of IL-1 beta, IL-6, and TNF-alpha, i.e., three immunoregulatory cytokines mainly secreted by activated monocytes/macrophages. Using the polymerase chain reaction technique, analyses of the mRNA levels for each of the three monokines after viral infection indicated that the effect exerted by each of these herpesviruses on cytokine synthesis by human PBMC was detectable at the transcriptional level. Different amounts of IL-1 beta protein were detected in infected PBMC cultures, HHV-6 being the strongest IL-1 beta up-regulatory among these three herpesviruses. Spontaneous releases of IL-6 and TNF-alpha were found reduced after infection by HHV-6 and EBV, respectively. In comparison to EBV and HHV-6, HSV-1 proved to be a weak monokine enhancer. Results of coinfection studies indicated that virus-induced suppressive effects on cytokine synthesis are dominant. In fact, EBV inhibited TNF-alpha synthesis even in the presence of HHV-6, a strong up-regulator of TNF-alpha synthesis. Similarly, EBV was unable to stimulate IL-6 production in the presence of HHV-6. Viral structural component(s) appeared to be responsible for the up-regulation of IL-6 by both EBV and HSV-1, and of TNF-alpha by HSV-1. Taken together, our observations illustrate that herpesviruses can selectively regulate cytokine synthesis thereby disturbing immune homeostasis; this effect may favor pathogenic events, including the reactivation and/or spread of other infectious agents within the host.

Infection of peripheral blood mononuclear cells by herpes simplex and Epstein-Barr viruses. Differential induction of interleukin 6 and tumor necrosis factor-alpha.

Infection by herpesviruses can result in profound immunosuppressive or immunomodulatory effects. However, no significant information is available on the effect of such infections on the production of immunoregulatory cytokines. We studied the kinetics of production of two monocyte-derived cytokines, interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF alpha), induced by Epstein-Barr virus (EBV) and herpes simplex virus type 1 (HSV-1) in peripheral blood mononuclear cell cultures and in fractionated cell populations. We observed that, when compared to HSV-1, EBV is a stronger inducer of IL-6. In EBV-infected cultures, IL-6 protein was detected at day 1 postinfection and gradually increased with time. In contrast, lower amounts of IL-6 were detected 5 d postinfection in HSV-1-infected cultures. HSV-1-infected cultures secreted significant amounts of TNF alpha protein after 5 d of culture and reached a maximal level of production at day 7, whereas EBV inhibited TNF alpha production. In fractionated cell populations, monocytic cells were found to be the main source of IL-6 synthesis after EBV or HSV-1 infection. However, TNF alpha synthesis in HSV-1-infected cultures was from both B and monocytic cells. By using the polymerase chain reaction technique we show that, after infection by these two herpesviruses, differences in cytokine gene products are also observed at the transcriptional level. These observations demonstrate that EBV and HSV-1 exert differential effects on IL-6 and TNF alpha gene transcription and on the resulting protein secretion in human mononuclear blood cells.

Induction of monocytic differentiation and NF-kappa B-like activities by human immunodeficiency virus 1 infection of myelomonoblastic cells.

The effects of human immunodeficiency virus 1 (HIV-1) infection on cellular differentiation and NF-kappa B DNA binding activity have been investigated in a new model of myeloid differentiation. PLB-985 cells represent a bipotential myelomonoblastic cell population capable of either granulocytic or monocytic differentiation after induction with appropriate inducers. By virtue of the presence of CD4 on the cell surface, PLB-985 cells were chronically infected with HIV-1 strain IIIB. PLB-IIIB cells clearly possessed a more monocytic phenotype than the parental myeloblasts, as determined by differential staining, increased expression of the myeloid-specific surface markers, and transcription of the c-fms proto-oncogene. NF-kappa B binding activity was inducible by tumor necrosis factor and phorbol myristate acetate in PLB-985. However, in PLB-IIIB cells, constitutive expression of a novel NF-kappa B complex was detected, composed of proteins ranging between 70 and 110 kD. These proteins interacted specifically with the symmetric NF-kappa B site from the interferon beta (IFN-beta) promoter. Mutations affecting the 5' guanine residues of the kappa B site were unable to compete for these NF-kappa B-related proteins. Inducibility of endogenous IFN-beta and IFN-alpha RNA was also increased in PLB-IIIB cells. These studies indicate that HIV-1 infection of myelomonoblastic cells may select for a more mature monocytic phenotype and that unique subunit associations of NF-kappa B DNA binding proteins may contribute to differential NF-kappa B-mediated gene expression.

Activation of cytokine genes in HIV-1 infected myelomonoblastic cells by phorbol ester and tumor necrosis factor.

The differential production of inflammatory cytokines (IL-1 alpha, IL-1 beta, IL-6, and TNF-alpha) was analyzed in the PLB-985 myelomonoblastic cell line, chronically infected or not by the IIIB strain of HIV-1. After treatment with phorbol ester (PMA) or TNF-alpha, a 20- to 40-fold increase in the level of IL-1 beta mRNA was observed in the HIV-infected PLB-IIIB as compared with the parental PLB-985 cells. The majority of the IL-1 beta activity detected in both cell types remained cell associated. In contrast, TNF-alpha mRNA levels were increased in both infected and uninfected cells; the t1/2 of TNF RNA was 90 min in uninfected cells and 30 min in HIV-infected cells. Interestingly, about 14-fold more TNF activity was secreted from PLB-IIIB than from similarly stimulated PLB-985 cells, indicating an enhanced translational efficiency of TNF RNA in PLB-IIIB cells. The PMA- or TNF-induced levels of IL-1 alpha mRNA did not vary significantly between the two cell types whereas IL-6 was poorly inducible in both cells. These results illustrate a differential cytokine response to HIV-1 infection in myeloid cells and demonstrate that HIV-1 infection of myelomonoblastic cells may alter both transcriptional and translational mechanisms controlling cytokine expression.

Differential susceptibilities of U-937 cell clones to infection by human immunodeficiency virus type 1.

Single-cell clones derived from the U-937 monocytic cell line were studied for susceptibility to infection by human immunodeficiency virus type 1 (HIV-1). Of four such clones, we found that three (UC12, UC14, and UC18) supported replication of HIV-1 more efficiently than parental U-937 cells, as measured by reverse transcriptase activity and p24 core antigen production. In contrast, another clone (UC11) showed only baseline infection throughout an 8-week culture period, before finally becoming positive for expression of viral antigen. This differential susceptibility to infection directly correlated with accumulation of intracellular viral DNA. Furthermore, the UC11 clone expressed lower levels of Sendai virus-inducible tumor necrosis factor alpha mRNA than did the UC12 or UC18 clones. Susceptibility to infection did not correlate with expression of cell surface CD4, since all clones expressed similar levels of CD4 mRNA and surface membrane CD4 protein. Prior exposure of both susceptible UC18 and resistant UC11 clones to Leu3a antibody completely blocked infection by HIV-1, suggesting that no other independent receptors were recognized by the virus.