Inhibition of HIV-1 replication by cyclopentenone prostaglandins in acutely infected human cells. Evidence for a transcriptional block.

Cyclopentenone prostaglandins (PGs) inhibit virus replication in several DNA and RNA virus models, in vitro and in vivo. In the present report we demonstrate that the cyclopentenone prostaglandins PGA(1) and PGJ(2) at nontoxic concentrations can dramatically suppress HIV-1 replication during acute infection in CEM-SS cells. PGs did not affect HIV-1 adsorption, penetration, reverse transcriptase activity nor viral DNA accumulation in HIV-1 infected cells. A dramatic reduction in HIV-1 mRNA levels was detected up to 48-72 h after infection (p.i.) in PG-treated cells, and HIV-1 protein synthesis was greatly reduced by a single PG-treatment up to 96 h p.i. Repeated PGA(1)-treatments were effective in protecting CEM-SS cells by the cytopathic effect of the virus, and in dramatically reducing HIV-1 RNA levels up to 7 d after infection. The antiviral effect was not mediated by alterations in the expression of alpha-, beta-, or gamma-interferon,TNFalpha, TNFbeta, IL6, and IL10 in HIV-infected CEM-SS cells. The fact that prostaglandins are used clinically in the treatment of several diseases, suggests a potential use of cyclopentenone PGs in the treatment of HIV-infection.

Murine interferon-alpha1 gene-transduced ESb tumor cells are rejected by host-mediated mechanisms despite resistance of the parental tumor to interferon-alpha/beta therapy.

The highly metastatic ESb tumor is totally resistant to murine interferon-alpha/beta (IFN-alpha/beta) therapy, regardless of the number of cells injected or the route of inoculation. In contrast, as we show herein, mouse IFN-alpha1-transduced ESb tumor cells were inhibited markedly when injected subcutaneously into immunocompetent mice. IFN-producing ESb tumor rejection was mediated by the immune system, because these tumor cells grew normally in immunosuppressed mice. Tumor regression was accompanied by extensive necrosis and cellular infiltrates in the tumor area. These results further support the use of IFN-alpha in cytokine gene therapy of cancer and suggest the advantage of using gene transfer rather than cytokine administration to enhance an antitumor immune response.

Inhibition of HIV-1 transcription by cyclopentenone prostaglandin A1 in Jurkat T lymphocytes.

Cyclopentenone prostaglandins inhibit virus replication in several DNA and RNA virus models. In this report we investigated the effect of prostaglandin A1 (PGA1) on HIV-1 transcription in human CD4+ Jurkat T lymphocyte cells. A dramatic reduction of HIV-1 RNA levels was detected up to seven days post infection in both unstimulated and phorbol 12-mystrate 13-acetate (PMA)-stimulated cells treated with PGA1- PGA1 treatment of cells was also effective in inhibiting the transcription of a chloramphenicol acetyltransferase (CAT) reporter gene, under the control of HIV-1 LTR, in Jurkat-Tat cells. We also show that PGA1 induced the synthesis of 70-kDa heat-shock protein (HSP70) in this cell system and the induction correlated with the drug-antiviral activity. PGA1 was also found to induce the loss of the tumor suppressor p53 protein, in the "proliferative" conformation, in a time correlation with the induction of the HSP70 As the "proliferative" p53 has been involved in the positive trans-activation of the HIV-1 LTR its depletion could contribute to the inhibitory mechanisms of PGA1 on virus transcription.

Stable transfection of provirus of human immunodeficiency virus into a murine packaging cell line.

In order to generate HIV (murine leukemia virus (MuLV)) pseudotypes, HIV genome was transfected into the ecotropic murine packaging cell line (GP+E86) and four of the nine transfected clones were extensively characterized. One clone (801), harbouring a full copy of integrated HIV sequences, exhibited a detectable level of intracellular HIV p24 antigen expression. Northern blot analysis revealed that clone 801 expressed all three classes of HIV mRNAs. Multispliced 2 kb mRNAs were detected in another clone (8.14). Two other clones (1.31 and 1.32) also exhibited a complete HIV provirus, but did not show any viral expression, as evaluated by Northern blot analysis or HIV p24 ELISA. Reverse transcription-polymerase chain reaction (RT-PCR) experiments revealed the presence of full length genomic RNA in four transfected clones, which were extensively characterized. A co-cultivation of clone 801 with human CD4' cells resulted in syncytia formation. By electron microscopy, mature HIV particles were observed after co-cultivation of uninfected C8166 cells with 801 cells. These results demonstrated that the murine clone was stably transfected with the complete HIV genome and was capable of shuttling infectious HIV to human cells. Clone 801 was co-cultivated with murine NIH-3T3 fibroblasts. In several experiments, HIV infection of NIH-3T3 cells was revealed by PCR technique. Thus, 801 cells appear to produce low levels of HIV (MuLV) pseudotypes capable of transferring the HIV genome into mouse cells.

Detection of antibodies to strain-specific and cross-reactive antigenic determinants on the haemagglutinin of influenza viruses A/Texas/1/77 and A/Bangkok/1/79 in human sera. Brief report.

The antibody response to antigenic determinants on the haemagglutinin molecule of A/Texas/77 and A/Bangkok/79 strains was analysed by SRH of virus-absorbed sera, in human sera collected from persons of different ages following natural infection or immunization. The results have shown, as expected, low and high frequencies of strain-specific antibodies in sera of adults and young children respectively. However, in the latter group antibodies to cross-reactive antigens were also detected.

Comparative electrophoretic study of polypeptides of influenza A/H3N2 viruses isolated in circumscribed geographical areas.

Two distinct groups of influenza A/H3N2 viruses, closely related to A/Bangkok/1/79 and to A/Belgium/2/81, have been chosen from viruses isolated in Italy during 1981 to 1983 with the aim of analysing the biochemical composition of their polypeptides. The strains of each group have shown differences in electrophoretic migration rates in one or more proteins in comparison to the prototype viruses. Polypeptide mobility variations among isolates from circumscribed geographical areas and from single outbreaks have also been observed. In particular, there was a high degree of variability in the NS1 protein. The detection of biochemical differences among identical antigenic variants, probably the result of point mutations in polypeptide sequences or of genetic reassortment among different co-circulating human viruses, is a further expression of the peculiar ability of the influenza A virus to exhibit variation in internal proteins during its circulation.

Synergistic anti-tumor effects of combined IL-1/IFN-alpha/beta therapy in mice injected with metastatic Friend erythroleukemia cells.

Peritumoral injection of relatively low doses of either mouse interferon (IFN)-alpha/beta (10,000-20,000 units/injection) or of recombinant human interleukin-1 (IL-1) beta (125-250 ng/injection) in mice transplanted s.c. with Friend erythroleukemia cells (FLC) resulted in some inhibition of primary tumor growth, inhibition of liver and splenic metastases and increased survival time. A synergistic anti-tumor effect was observed in mice injected with both IL-1 and IFN-alpha/beta. Highly purified mouse IFN-beta also exerted a synergistic anti-tumor effect when combined with IL-1-beta in mice injected with FLC. The anti-tumor action of IL-1/IFN was markedly reduced in mice treated with antibodies to CD4 antigens. Antibodies to asialo-GM1 also diminished the anti-tumor effect by the combined cytokine treatment. The combined IL-1/IFN therapy was effective in NK-deficient bg/bg mice, although the extent of the anti-tumor response in these mice was less than that observed in bg/+mice.

Correlation between the sensitivity or resistance to IL-2 and the response to cyclophosphamide of 4 tumors transplantable in the same murine host.

We have studied the anti-tumor response to cyclophosphamide (CTX) in DBA/2 mice transplanted s.c. with 4 tumors exhibiting different responses to IL-2: ESb lymphoma and Friend leukemia cells (non-responsive or poorly responsive, respectively), p11-R-Eb and Eb lymphoma cells (both highly responsive to IL-2). CTX injections on days 7, 14 and 21 resulted in a significant anti-tumor response in mice transplanted s.c. with Friend leukemia cells or ESb cells, whereas no anti-tumor effect was observed in mice injected with Eb or p11-R-Eb cells. All 4 tumor cell lines were equally sensitive to the cytotoxic effects of mafosfamide, an in vitro active analogue of CTX. To define the host mechanisms responsible for the lack of an anti-tumor effect of CTX in mice transplanted with IL-2-responsive tumors, we studied several aspects of the spontaneous or IL-2-induced anti-tumor response in mice transplanted with p11-R-Eb cells. Injection of monoclonal antibodies (MAbs) to IFN-gamma completely abolished the anti-tumor effects of IL-2. Using a Winn assay, clear-cut anti-tumor activity was found in spleen cells from mice transplanted with the IL-2-responsive tumors. This activity was abolished by CTX, which also abrogated the anti-tumor response to IL-2 in mice injected with p11-R-Eb cells. Our results indicate an inverse correlation between sensitivity to IL-2 and response to CTX and emphasize the importance of initial host-tumor interaction in determining the type of response to IL-2 or CTX.

Antigenic and biochemical analysis of influenza "A" H3N2 viruses isolated from pigs.

Four influenza A-H3N2 viruses isolated in pigs from different herds in Central Italy in the period 1981/82 have been antigenically and biochemically analysed. Three of them A/Sw/Italy/2/81, A/Sw/Italy/7/81, A/Sw/Italy/8/82 were found to be serologically related to A/Bangkok/1/79 (H3N2). These three viruses were shown to have an identical electrophoretic pattern, as regards virus induced polypeptides and were clearly distinguishable from the virus A/Sw/Italy/6/81 which was antigenically related to A/England/42/72 (H3N2) and A/Sw/Taiwan/7310/70 as shown by specific monoclonal and polyclonal antisera. The observed biochemical variations underline the importance of the changes occurring by genetic reassortments or mutations in human influenza viruses, during their maintenance in pigs.

Comparison of haemagglutination-inhibition and single radial haemolysis techniques for detecting antibodies to influenza A and B viruses.

The sensitivities of haemagglutination-inhibition (HI) and single radial haemolysis (SRH) techniques in detecting antibodies against influenza A/Bangkok/1/79, A/Brazil/11/78, B/Singapore/222/79, B/Hong Kong/5/72 strains, in human sera were compared. For antibodies to influenza B viruses the HI tests employing ether-treated antigens were also evaluated. The SRH technique appears to be more sensitive for detecting protective titres of antibodies against influenza B strains and influenza A/Brazil/11/78.

HBV-DNA, HBeAg/anti-HBe serological status in hepatitis B chronic individuals from central Italy.

A population of 488 HBsAg carrier individuals, from central Italy, classified on the basis of biochemical, clinical and histological parameters, was analysed for the presence of HBV-DNA in serum and its relationship with HBeAg/anti-HBe markers. The prevalence of HBV-DNA was 32.8% in chronic patients with biopsy-proven liver disease, and 20 and 4.3% respectively in asymptomatic carriers with and without altered ALT levels. The values in chronic patients were correlated with the histological activity. Concordance of HBV-DNA presence and HBeAg positivity was observed in only 61.4% of cases. However HBV-DNA prevalence in sera of anti-HBe positive individuals was very low in asymptomatic carriers with normal ALT levels (2.5%). Higher values were observed in anti-HBe positive chronic patients (15.8%) and in carriers occasionally found with changes in ALT without any other clinical sign of illness (16.7%). These data would indicate that HBV-DNA is the serological marker which is most closely related to liver disease.

Induction of the heat-shock response by antiviral prostaglandins in human cells infected with human immunodeficiency virus type 1.

Cyclopentenone prostaglandins inhibit the replication of several DNA and RNA viruses, including retroviruses. The antiviral activity has been associated with the induction of a 70-kDa heat-shock protein (HSP70), via activation of the heat-shock transcription factor (HSF) in infected cells. In the present study we investigated the effect of prostaglandin A1 (PGA1) on the regulation of HSP70 gene expression as well as on viral RNA and protein synthesis in CEM-SS cells during acute infection with human immunodeficiency virus type 1 (HIV-1). We report that HIV-1 infection does not alter HSF activation by PGA1, whereas it causes an increase in intracellular HSP70 mRNA levels, as a result of enhanced HSP70 mRNA stability. We also show that, as reported in studies of different virus/host cell models, PGA1 inhibits HIV-1 replication by acting at multiple levels during HIV-1 infection. In addition to the previously reported block of HIV-1 mRNA transcription, PGA1 was also found to inhibit viral protein synthesis. These results, together with the fact that prostaglandins are used clinically in the treatment of several diseases, open new perspectives in the search for novel antiretroviral drugs.

Hepatitis B infections in the Arsi region of Ethiopia.

In a sample of inhabitants of the Arsi region of Ethiopia prevalence of hepatitis B is around 80% in the age group 20-24. In addition to age, sex and size of family, exposure to tribal practices is a determinant of seropositivity in this group accounting for as much as 20% of the total burden of the infection. Waiting for a mass vaccination campaign, presently unrealistic in this area of the world, health education, as part of a comprehensive primary health care program, has to be considered as a potentially effective preventive tool.

Local and systemic response of mice to interferon-alpha 1-transfected Friend leukemia cells.

DBA/2 mice were injected subcutaneously with an interferon (IFN)-alpha/beta-resistant line of Friend erythroleukemia cells (FLC) transfected with the mouse IFN-alpha 1 gene. These tumor cells produced IFN constitutively, and mice had persistently high levels of IFN in the circulation. We examined the IFN-induced host mechanisms responsible for the local inhibition of growth of these IFN-alpha-transfected FLC and some of the unusual systemic effects of constant interferonemia such as extramedullary hematopoiesis in the liver, an increase in myeloid cells in the spleen, and persistently elevated splenic natural killer (NK) cell activity. In addition, both DBA/2 +/bg and beige mice developed a rapid and specific resistance to intravenous challenge with parental FLC. In previous experiments DBA/2 beige mice could not be protected by exogenous IFN-alpha/beta. The differences in the response of mice to the constitutive production of IFN-alpha by IFN-alpha-transfected tumor cells and their response to exogenous IFN is discussed in terms of the effects of IFN on the host and of antitumor therapy.

Interferon (IFN)-beta gene transfer into TS/A adenocarcinoma cells and comparison with IFN-alpha: differential effects on tumorigenicity and host response.

Our group had previously shown that transfer of the mouse interferon (IFN)-alpha1 gene into the metastasizing TS/A mammary adenocarcinoma resulted in T-cell-mediated tumor rejection and development of antitumor immunity. Moreover, we had shown that the metastatic ability of TS/A tumor cells producing IFN-alpha was strongly impaired, whereas IFN-gamma expression did not influence or augmented metastasis formation by TS/A cells. In this study, we have analyzed the in vitro and in vivo behavior of various TS/A tumor cell clones isolated after the transduction with a recombinant retroviral vector carrying the mouse IFN-beta gene. We have also compared the tumorigenicity of these clones with that of TS/A cells expressing IFN-alpha1. BALB/c mice were inoculated subcutaneously with parental TS/A cells, transduction control TS/A cells, or TS/A cells producing IFN-alpha or IFN-beta. Tumor growth was evaluated by the measurement of tumor masses and analysis of survival. The features of tumor growth and rejection were examined by histological and immunohistochemical analyses. The metastatic ability of parental TS/A cells, transduction control TS/A cells, or TS/A cells producing IFN-alpha, IFN-beta, or IFN-gamma was evaluated after intravenous injection of the tumor cells into BALB/c mice by counting of the lung metastatic nodules and analysis of survival. A strong inhibition of tumorigenicity and development of tumor immunity were observed upon subcutaneous injection of syngeneic mice with TS/A tumor cells producing high amounts of IFN-beta, but not with clones expressing low levels of the cytokine, as observed for cells expressing IFN-alpha. IFN-alpha secretion by TS/A cells at the site of tumor growth induced a stronger inflammatory response as compared with IFN-beta, which appeared to be more active in the inhibition of tumor-induced angiogenesis. Notably, the metastatic ability of IFN-beta-producing TS/A cells after intravenous injection was either not affected or only slightly impaired as compared with parental TS/A tumor cells. In contrast, even cells producing low levels of IFN-alpha proved to be poorly metastatic. These findings represent the first comparison of the effectiveness of IFN-alpha versus IFN-beta produced by genetically modified cells on their tumorigenic behavior and suggest the existence of some notable differences in the capabilities of these two cytokines to induce a host antitumor reactivity in mice.

[Antibody response to trivalent anti-influenza vaccination (inactivated virus) A/Texas/1/77 H3N2), A/URSS/90/77 (H1N1), B/Hong Kong/8/73]. / Risposta anticorpale alla vaccinazione anti-influenzale trivalente (A virus inattivato) A/Texas/1/77 (H3N2), A/URSS/90/77 (H1N1), B/Hong Kong/8/73.

Seventy-five young recruits received an intramuscular dose of anti-influenza virus vaccine containing 300 U.I. of A/Texas/1/77 (H3N2), A/URSS/90/77 (H1N1), B/Hong Kong/8/73 strains. Antibody responses were detected by HI and SRH tests: immunogenicity of the preparation was different for the individual vaccine strain in spite of the similar amount of antigenic content, and the immunity conferred by vaccine strains did not significantly extend to new influenza virus strains which prevailed in 1979/80 winter season with the exception for A/Brazil/11/78 (H1N1).

[Antibody response to an anti-influenza vaccine of inactivated whole virus, titrated in micrograms, used in the 1980/81 season]. / Risposta anticorpale al vaccino anti-influenzale A virus intero inattivato, titolato in microgrammi, in uso nella stagione 1980/81.

Antibody response of 68 healthy young-adult volunteers to A/Bangkok/1/79 (H3N2), A/Brazil/11/78 (H1N1), B/Singapore/222/79 trivalent anti-influenza virus vaccine was studied by haemagglutination inhibition and single radial haemolysis techniques. The results of this study indicate that immunogenicity of the individual components of the vaccine (10 micrograms each) varied significantly, the highest frequence of antibody response occurring for A/Brazil influenza virus strain and the lowest for B/Singapore.