Rheumatic symptoms in patients with human immunodeficiency virus are related to levels of tumor necrosis factor-alpha but not to viral load.

Infection with human immunodeficiency virus (HIV) can lead to osteoarticular involvement, usually in the late stages. The pathogenesis of these symptoms has usually been attributed to viral load or to dysregulated cytokine production. We evaluated the presence of rheumatic symptoms and levels of tumor necrosis factor (TNF)-alpha viral load and CD4 count in 46 patients with HIV from southern Italy. The prevalence of rheumatic symptoms was 23.9%; CD4 count and viral load presented no statistically significant differences between patients with rheumatic symptoms and patients without osteoarticular involvement, whereas TNF-alpha levels were increased in HIV patients with arthralgias compared with those in patients without arthralgias (p = 0.02). Evidence that TNF-alpha is increased in patients with osteoarticular or soft tissue involvement is a clear index of the pivotal role this cytokine plays in the pathogenesis of these manifestations.

Role of interleukin-18 in peripheral blood mononuclear cells infected with human herpes virus type 6.

OBJECTIVE: Interleukin 18 (IL-18) production represents a critical step in the polarization of the Th1 immune response. Human herpes virus type 6 (HHV-6) possesses a peculiar tropism for immunocompetent cells. To understand the relationships among immunocompetent cells, HHV-6 and cytokines, the role of IL-18 during infection of peripheral blood mononuclear cells (PBMC) with HHV-6 was evaluated. METHODS: PBMC were obtained from healthy HHV-6-seronegative donors, after centrifugation of heparinized venous blood over a Ficoll-Hypaque gradient. Supernatants from PBMC were analyzed for the presence of cytokines. To study the effects of exogenous recombinant human (rh) IL-18 on HHV-6 replication, the number of cells expressing viral antigens and the amount of extracellular virus were analysed. RESULTS: No basal production of IL-18 was found in supernatants of unstimulated PBMC. Appreciable amounts of the cytokine were produced by lipopolysaccharide (LPS)-stimulated PBMC. HHV-6 infection of LPS-treated PBMC downregulated IL-18 production. It was found that the addition of rhIL-18 to HHV-6-infected PBMC downregulated the percentage of antigen-positive cells and the release of extracellular virus. CONCLUSION: Impairment of IL-18 release, which is involved in the induction of antiviral cytokines, such as interferon-gamma, could represent a strategy of the virus to evade the immune response of the host.

Role of IL-15 on monocytic resistance to human herpesvirus 6 infection.

Interleukin-15 (IL-15) is a cytokine that possesses a variety of biological functions, including stimulation and maintenance of cellular immune responses. Recently, it has been demonstrated that Human Herpes virus type 6 (HHV-6) enhances NK activity of human PBMC by inducing IL-15. HHV-6 is a typical immunosuppressive agent, as suggested by its tropism for both CD4+ and CD8+ T cells, B cells, monocytes/macrophages, megakaryocytes and NK cells. Moreover, several studies have indicated that mononuclear phagocyte resistance to virus infection is influenced by the cellular differentiation state. This paper describes the effect of pretreatment "in vitro" with IL-15 on the resistance of human monocytes (HM) to HHV-6 infection. Our results demonstrate that undifferentiated HM were highly resistant to HHV-6 infection, whereas HM pretreated with human recombinant IL-15 showed an increased permissiveness for HHV-6 infection. This permissiveness was characterised by higher release of extracellular virus as well as an increased percentage of antigen positive cells. Moreover, we evaluated IL-15 production after the addition of HHV-6 to monocytes precultured in different experimental conditions. Our data indicate that HHV-6-induced IL-15 production by human monocytes is not affected by the condition of "in vitro" precultivation/differentiation. Furthermore, the neutralization of IL-15 induced by HHV-6 in differentiated monocytes did not affect viral replication. These findings suggest that IL-15 acts only on the mechanisms of cellular differentiation, rendering HM more susceptible to HHV-6 infection, without interfering with virus replication.

Murine gamma-herpesvirus 68 glycoprotein 150 protects against virus-induced mononucleosis: a model system for gamma-herpesvirus vaccination.

Murine gamma-herpesvirus 68 (MHV-68) is a model for the study of the pathogenesis of gamma-herpesviruses. Epstein-Barr virus (EBV) is a highly related gamma-herpesvirus that causes significant disease in humans. The major membrane antigen gp350 of EBV is a candidate vaccine antigen for protection against EBV-related disease. An MHV-68 glycoprotein, gp150, has significant homology to EBV gp350. We have therefore used the MHV-68 gp150 to model the potential efficacy of EBV gp350 in protecting from virus-associated disease. A recombinant vaccinia virus expressing MHV-68 gp150 was constructed. This recombinant vaccinia virus was used to infect mice via the subcutaneous route. This vaccination resulted in production of MHV-68-neutralising antibodies. Mice were then challenged intra-nasally with MHV-68. MHV-68-associated mononucleosis was virtually abrogated in immunised mice. However, mice did establish MHV-68 latency. The results suggest that gp350 may be effective as an immunogen to prevent EBV-associated infectious mononucleosis in humans that are EBV-seronegative.

Comparative effect of gentamicin and pefloxacin treatment on the late stages of mouse typhoid.

The present study compares the ability of gentamicin and pefloxacin to eradicate a Salmonella infection in BALB/c mice when the treatment is instituted in the late stages of the infection. The results indicate that pefloxacin is highly effective in the treatment of mouse typhoid even when the therapy is instituted after the suppression of bacterial growth in the reticuloendothelial system (RES). Conversely, gentamicin treatment only reduced the bacterial load in the RES of infected mice, but neither induced the clearance of the organisms from the RES, nor prevented the resurgence of bacterial growth. Even when using gentamicin at a high dosage, bacterial clearance could not be accomplished.

Cellular uptake and activity of rufloxacin in different cell types and professional phagocytic cells.

The penetration of the new quinolene rufloxacin into human professional phagocytic cells and different cell types was determined. The intracellular distribution was demonstrated in all cells studied. At 4 degrees C the transport of rufloxacin was reduced. An intracellular dose-dependent activity was demonstrated for rufloxacin in monocytes and granulocytes infected with E. coli and S. aureus. In all the experiments rufloxacin was able to eliminate all intracellular bacteria.

Effects of rufloxacin in Salmonella typhimurium infection in mice.

This study was undertaken to investigate the efficacy of rufloxacin, a new quinolone which is interesting due to its pharmacokinetics characterized by a long plasma half-life, in the treatment of systemic salmonella infections in the mouse typhoid model. Innately susceptible BALB/c and resistant CBA mice were used to investigate the efficacy of rufloxacin in controlling systemic salmonella infections when given for brief or prolonged periods. The present study shows that rufloxacin is not only very effective on both mouse strains, but can completely eradicate the salmonellae from livers and spleens when given early in the infection of CBA resistant mice.

Fluorocontaining D-cycloserines. Synthesis and in vitro evaluation of antimicrobial and antiviral activities.

Some fluoroacylderivatives at the side chain NH2 of D-cycloserine were synthesized and evaluated in vitro for antimicrobial activity against bacteria and tubercular or non-tubercular mycobacteria. Against the used Gram-positive and Gram-negative strains only trifluoroacetamide 1 exhibited comparable MIC values and lower MBC values than those of parent antibiotic. Other fluoroacycloserines, inactive at all on these bacteria, were found to inhibit the growth of mycobacteria when tested in liquid media. The in vitro anti-Herpex Simplex virus type-2 (HSV-2) activity was also investigated on HEp-2 and Vero cells. The obtained results demonstrated an antiviral activity of the compounds 1 and 3 when tested on Vero cell-lines, whereas the same cycloserine is inactive.

Generation of superoxide anion and candidacidal activity by lipopolysaccharide-treated macrophages from patients affected by neoplasia.

Macrophages, derived from in vitro cultured monocytes from both healthy donors and patients affected by metastatic breast cancer, treated or not with Escherichia coli lipopolysaccharide (LPS), were tested for phagocytosis and intracellular killing of Candida albicans and superoxide anion release. We found a marked impairment in intracellular killing closely linked to the lack of superoxide production in macrophages from patients affected by neoplasia treated or not with LPS. On the other hand, the LPS treatment significantly enhanced the phagocytic activity of all the macrophage populations tested, except for phagocytes obtained from patients affected by neoplasia and differentiated in autologous serum.

Serum TNF alpha in mouse typhoid and enhancement of a Salmonella infection by anti-TNF alpha antibodies.

Tumour necrosis factor alpha (TNF alpha) was detected by the L929 cell assay in the sera of mice 1 h after large i.v. inocula of virulent Salmonella typhimurium C5. TNF alpha was not detectable in sera from innately susceptible BALB/c mice during the course of a lethal infection commencing from a low inoculum, or from resistant A/J mice during the course of a lethal or sublethal infection, but only 1 h after i.v. challenge with large numbers of organisms. Administration of a single dose of rabbit polyclonal anti-TNF alpha antiserum on day 1 had no effect on the early course of a lethal infection in A/J mice. However, the same treatment exacerbated a sublethal infection in A/J mice. Anti-TNF alpha treatment did not accelerate the early bacterial net growth rate in the RES. Instead, the cfu count in treated mice continued to increase past the point at which the host response suppressed a further increase in bacterial numbers (the plateau phase) in normal controls. A second dose of anti-TNF alpha antiserum on day 4 together with a higher but still sublethal challenge caused a lethal infection in A/J mice. The results indicate that TNF alpha is important in mediating the plateau phase in a salmonella infection, and its effect may be local.

Modulation of the intrinsic antiviral activity by Escherichia coli endotoxin in macrophages from patients with neoplasia.

Macrophages from patients with breast cancer showed an impairment of their antiviral activity. The capability to hinder herpes simplex virus type 2 replication of macrophages from healthy donors and from patients with breast cancer was compared to the in-vitro treatment with Escherichia coli lipopolysaccharide (LPS). The LPS showed a dose-dependent effect on the different macrophage populations studied. Nevertheless, macrophages from healthy donors appeared to be more sensitive to LPS in comparison with macrophages from the patients under our observation. On these cells LPS treatment was not able to modify the antiviral property, when these macrophages were differentiated in autologous serum.

Beta-lactam antibiotics (aztreonam, ampicillin, cefazolin and ceftazidime) in the control and eradication of Salmonella typhimurium in naturally resistant and susceptible mice.

This study was undertaken to investigate the efficacy of different beta-lactam antibiotics in the treatment of systemic salmonella infections in the mouse typhoid model. Innately susceptible BALB/c (Itys) and resistant CBA (Ityr) mice were used to investigate the efficacy of one monocyclic (aztreonam) and three bicyclic (ampicillin, cefazolin, ceftazidime) beta-lactam antibiotics in controlling systemic salmonella infections when given for brief or prolonged periods. The present study confirms and amplifies earlier reports on ampicillin therapy, demonstrates marked differences in the efficacy of the different antibiotics and shows that aztreonam is not only very effective but can completely eradicate the salmonellae from the RES when given early in the infection.

Role of exogenous interferons on intrinsic antiviral activity of macrophages from patients affected by neoplasia.

Macrophages derived from in vitro cultured monocytes were infected with herpes simplex virus type 2. A marked impairment in the intrinsic antiviral activity was found in macrophages obtained from patients with breast cancer or melanoma. Moreover, the antiviral activity of macrophages from healthy donors, differentiated in serum from patients with neoplasia, was also impaired. The aim of this work was the evaluation of alpha, beta, gamma exogenous interferon in restoring the intrinsic antiviral activity of macrophages from patients affected by breast cancer or melanoma under different conditions. Pretreatment of macrophages with alpha, beta interferons, but not gamma interferon, restored their impaired intrinsic antiviral activity.

Interferon release by LPS-treated macrophages from patients affected by neoplasia.

Concerning the modulatory role of LPS on immunocompetent cells, the production of interferon by macrophages primed with human gamma interferon (HUIFN gamma), was studied. In particular the production of IFN from primed macrophages of patients affected by breast cancer, differentiated in presence of autologous serum or in serum from healthy donors, was compared with the IFN production from macrophages of healthy donors. The levels of endotoxin-induced IFN were enhanced by priming macrophages with HUIFN gamma. The "in vitro" treatment with Escherichia coli LPS restores the interferon production of primed macrophages, obtained from patients affected by breast cancer, differentiated in presence of serum from healthy donors. Moreover, LPS treatment of primed macrophages from patients, differentiated in autologous serum, did not influence the interferon production of these cells. Nevertheless, primed macrophages from healthy donors appeared to be more sensitive to LPS treatment in comparison with primed macrophages from patients affected by breast cancer.

Role of Salmonella enteritidis lipopolysaccharide on anti-HSV activity of macrophages from different anatomical sites.

It is generally agreed that endotoxins from Gram-negative bacteria play a modulatory role on several macrophage functions. The intrinsic activity versus herpes simplex virus type 1 and type 2 of Kupffer cells, peritoneal and alveolar macrophages, harvested from normal and tumour-bearing rats, was evaluated. Moreover, the effects of different intravenous treatments with S. enteritidis endotoxin were investigated. The antiviral activity of peritoneal, alveolar macrophages and Kupffer cells from tumour-bearing rats is definitely impaired but it appears to be positively modulated by in-vivo administration of S. enteritidis lipopolysaccharide (LPS).

Modulation of macrophage functions by corynebacterium parvum preparations.

Corynebacterium parvum has been used as an anti-tumor agent in both animal experiments and clinical trials; nevertheless it is not well established the mechanism of action, since both T-dependent and T-independent ways of action have been proposed. On the other hand, mononuclear phagocytic system activation cannot be ruled out in the immunomodulation carried out by C. parvum. In the attempt to better understand the effects of C. parvum on macrophage functions, experiments were carried out on tumor-bearing rats with a decline of peritoneal macrophage activities as a result of the tumor development. For this purpose three different preparations of C. parvum were investigated: a) the first preparation was obtained by heat-inactivation of bacteria at 60 degrees C for 1h; b) the second by formalin-treatment of bacteria; c) the third obtained from Burrough Wellcome as a formaline-killed suspension in 0.01% w/v thiomersal saline. Each preparation was used at 7 mg/ml dry weight and administered subcutaneously, three days after tumor grafting. The results showed that all three preparations were capable to hinder the tumor mass growth. Macrophage functions as phagocytosis, intracellular killing, intrinsic and extrinsic anti-Herpes Simplex Virus activities, were restored to normal values by each of the preparations used. Nevertheless, concerning the chemotactic activity a discrepancy was noted among the three preparations, since the heat-inactivated one was able to carried out a complete restoration.