Setting of import tolerances for metalaxyl-M in oil palms fruits and peppercorn.

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant Syngenta Crop Protection AG submitted a request to the competent national authority in Belgium to set an import tolerance for the active substance metalaxyl-M in oil palms fruits and peppercorn (black, green and white). The data submitted in support of the request were found to be sufficient to derive MRL proposals for oil palms fruits and peppercorn. Adequate analytical methods for enforcement are available to control the residues of metalaxyl-M in the commodities under consideration at the validated limit of quantification (LOQ) of 0.01 mg/kg. Based on the risk assessment results, EFSA concluded that the short-term and long-term intake of residues resulting from the use of metalaxyl-M according to the authorised agricultural practices is unlikely to present a risk to consumer health.

Review of the existing maximum residue levels for spirodiclofen according to Article 12 of Regulation (EC) No 396/2005.

According to Article 12 of Regulation (EC) No 396/2005, EFSA has reviewed the maximum residue levels (MRLs) currently established at European level for the pesticide active substance spirodiclofen. Although this active substance is no longer authorised within the European Union, MRLs were established by the Codex Alimentarius Commission (codex maximum residue limits; CXLs) and import tolerances were reported by Member States (including the supporting residues data). Based on the assessment of the available data, EFSA assessed the CXLs and import tolerances requested, and a consumer risk assessment was carried out. Although no apparent risk to consumers was identified, as spirodiclofen is classified as carcinogenic 1B with threshold, all MRL proposals derived by EFSA still require further consideration by risk managers.

Setting of import tolerances for azoxystrobin in mangoes and oil palm fruits.

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant Syngenta Crop Protection AG submitted a request to the competent national authority in Austria to set an import tolerance for the active substance azoxystrobin in mangoes and oil palm fruits imported from Brazil and Colombia, respectively. The data submitted in support of the request were found to be sufficient to derive maximum residue level (MRL) proposals for mangoes and oil palm fruits. Adequate analytical methods for enforcement are available to control the residues of azoxystrobin on the commodities under consideration at the validated limit of quantification (LOQ) of 0.01 mg/kg. Based on the risk assessment results, noting that an acute risk assessment was not deemed necessary for azoxystrobin, EFSA concluded that the long-term intake of residues resulting from the uses of azoxystrobin according to the reported agricultural practices is unlikely to present a risk to consumer health.

Modification of the existing maximum residue levels for sodium 5-nitroguaiacolate, sodium o-nitrophenolate and sodium p-nitrophenolate (sodium nitrocompounds) in table olives and olives for oil production.

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant Asahi Chemical Europe s.r.o. submitted a request to the competent national authority in Greece to modify the existing maximum residue levels (MRLs) for the active substances sodium 5-nitroguaiacolate (Na 5-NG), sodium o-nitrophenolate (Na o-NP) and sodium p-nitrophenolate (Na p-NP) in table olives and olives for oil production in support of the intended SEU use. The data submitted in support of this MRL application were sufficient to derive an MRL of 0.12 mg/kg (at the combined limit of quantification (LOQ) of the three sodium nitrocompounds as validated in the framework of the residue trials). This higher MRL does not reflect residues in olives from the intended use but refers to occurrence of p-nitrophenolate (p-NP) from unidentified source. As p-NP was present in all untreated olive samples regardless of the country of origin and the year of the treatment, in some cases at levels above the enforcement LOQ of 0.01 mg/kg, the applicant analysed residue trial samples using a method with a higher validated LOQ of 0.1 mg/kg for Na p-NP. The competent authorities shall be aware that residues of p-NP at levels < 0.1 mg/kg in olives are not related to the use of sodium nitrocompounds on the crop but to other sources of unknown origin. The current analytical methods for enforcement control residues of sodium nitrocompounds in high oil content matrices at the validated LOQ of 0.01 mg/kg per substance (combined LOQ of 0.03 mg/kg). Based on the risk assessment results, EFSA concluded that the short-term and long-term intake of residues resulting from the use of sodium nitrocompounds according to the reported agricultural practice and occurrence of p-NP from unidentified source is unlikely to present a risk to consumer health.

Setting of import tolerances for chlorantraniliprole in oil palms fruits and oil palms kernels.

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant FMC Agro Ltd submitted a request to the competent national authority in the United Kingdom to set import tolerances for the active substance chlorantraniliprole in oil palms fruits and oil palms kernels. The data submitted in support of the request were found to be sufficient to derive maximum residue level (MRL) proposals for these products. Adequate analytical methods for enforcement are available to control the residues of chlorantraniliprole in the commodities under consideration at the validated limit of quantification (LOQ) of 0.01 mg/kg. Based on the risk assessment results, EFSA concluded that the long-term intake of residues resulting from the use of chlorantraniliprole according to the reported agricultural practice is unlikely to present a risk to consumer health.

Biological and physical characterization of the X4 HIV-1 suppressive factor secreted by LPS-stimulated human macrophages.

LPS-stimulated macrophages release soluble factors that inhibit HIV-1 infection in both CD4(+) T lymphocytes and macrophages. These inhibitory factors include the CCR5 ligands RANTES, MIP-1alpha and MIP-1beta, which selectively block R5 HIV-1 strains, and a still unidentified factor with activity against X4 HIV-1 strains that we designate soluble macrophage-derived anti-HIV factor (MDAF). Here, we used X4 HIV-1 strains as specific probes to investigate the biological and physical characteristics of MDAF without the confounding effect of CCR5-binding chemokines. We show that MDAF has a broad spectrum of action, as it blocks infection by HIV-1 strains of different genetic subtypes. MDAF is sensitive to heat and proteinase K treatment, and it appears to be preformed within MDM, in that it is rapidly released upon LPS stimulation and its production is insensitive to cycloheximide, an inhibitor of protein neosynthesis. The convergent results of different assays indicate that MDAF acts primarily at the level of viral entry. Finally, MDAF is distinct from several known cytokines that possess anti-HIV-1 activity, including IL-10, IL-12, IL-16, IFN-gamma and alpha-defensins. The biological and physical characterization of MDAF may be instrumental in devising effective new strategies for its identification.

Macrophages and HIV-1: dangerous liaisons.

HIV-1, like the other lentiviruses, has evolved the ability to infect nondividing cells including macrophages. HIV-1 replication in monocytes/macrophages entails peculiar features and differs in many respects from that in CD4 T lymphocytes. HIV-1 exhibits different tropism for CD4 T cells and macrophages. The virus can enter macrophages via several routes. Mitosis is not required for nuclear import of viral DNA or for its integration into the host cell genome. Specific cellular factors are required for HIV-1 transcription in macrophages. The assembly and budding of viral particles in macrophages take place in late endosomal compartments. Viral particles can use the exosome pathway to exit cells. Given their functions in host defence against pathogens and the regulation of the immune response plus their permissivity to HIV-1 infection, monocytes/macrophages exert a dual role in HIV infection. They contribute to the establishment and persistence of HIV-1 infection, and may activate surrounding T cells favouring their infection. Furthermore, monocytes/macrophages act as a Trojan horse to transmit HIV-1 to the central nervous system. They also exhibit antiviral activity and express many molecules that inhibit HIV-1 replication. Activated microglia and macrophages may also exert a neurotrophic and neuroprotective effect on infected brain regulating glutamate metabolism or by secretion of neurotrophins. This review will discuss specific aspects of viral replication in monocytes/macrophages and the role of their interactions with the cellular environment in HIV-1 infection swinging between protection and pathogenesis.

Selective suppression of IL-12 production by human herpesvirus 6.

Human herpesvirus 6 (HHV-6) is a potentially immunosuppressive agent that has been suggested to act as a cofactor in the progression of HIV disease. Exposure of human macrophages to HHV-6A or HHV-6B profoundly impaired their ability to produce interleukin 12 (IL-12) upon stimulation with interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS). By contrast, the production of tumor necrosis factor-alpha (TNF-alpha); regulated on activation, normal T-cell expressed and secreted (RANTES); and macrophage inflammatory protein 1 beta (MIP-1 beta) was not negatively affected. To exclude the involvement of IL-12-suppressive cytokines, such as IL-10 and TNF-alpha, the viral stocks were fractionated by ultra-centrifugation. The bulk of the suppressive activity was recovered within the virion-rich pelleted fraction that was virtually devoid of such cytokines. IL-12 suppression was independent of viral replication, and the effect was not abrogated upon ultraviolet-light inactivation of the viral inoculum. The mechanism of HHV-6-mediated IL-12 suppression was investigated by RNase protection assays, which demonstrated unaltered levels of IL-12 p35 mRNA and only a modest reduction in p40 mRNA, which was insufficient to account for the near-complete loss of both extracellular and intracellular IL-12 protein. Moreover, both the IFN-gamma and the LPS signaling pathways were intact in HHV-6-treated cells. These data suggest that HHV-6 can dramatically affect the generation of effective cellular immune responses, providing a novel potential mechanism of HHV-6-mediated immunosuppression.

Chemokines as natural HIV antagonists.

The unexpected encounter between the fields of HIV and chemokines has opened new perspectives for understanding the mechanisms of AIDS pathogenesis, as well as for the development of effective therapies and vaccines. Selected chemokines act as potent natural inhibitors of HIV infection, as they bind and downmodulate chemokine receptors that serve as critical coreceptors for HIV to gain access into cells. The differential usage of the two major HIV coreceptors, CCR5 and CXCR4, determines the biological diversity among HIV variants. Most primary HIV strains use CCR5 as a coreceptor and thereby are sensitive to inhibition by the CCR5-ligand chemokines, RANTES, MIP-1alpha and MIP-1beta. The high level of expression of these proinflammatory chemokines in HIV-infected secondary lymphoid tissues may help to explain the inherently slow course of HIV disease. The crucial role played by CCR5 in the physiology of HIV infection is further attested by the near-complete resistance to HIV infection in people carrying a homozygous 32 bp deletion within the CCR5 gene (CCR5-delta32). A smaller proportion of HIV isolates, commonly emerging in concomitance with the clinical progression toward AIDS, uses CXCR4 as a coreceptor and is inhibited by the CXCR4 ligand, SDF-1. The high level of expresion of SDF-1 in the genital mucosa may help to explain the inefficient transmission of CXCR4-tropic HIV. Although chemokines or derivative-molecules could be exploited as therapeutic agents against HIV, the risk of inducing inflammatory side-effects or of interfering with the physiology of the homeostatic chemokine system represents a potential limitation. However, the ability of chemokines to block HIV infection can be uncoupled from their receptor-mediated signaling activity, thus providing a theoretical foundation for the rational design of safe and effective chemokine receptor inhibitors.

Inhibition of CXCR4-tropic HIV-1 infection by lipopolysaccharide: evidence of different mechanisms in macrophages and T lymphocytes.

Bacterial LPS protects primary human macrophages from infection by CCR5-tropic HIV-1 isolates through the release of the CC chemokines RANTES and macrophage inflammatory protein-1 alpha and -1 beta. Here, we show that LPS also suppresses infection of macrophages by CXCR4-tropic HIV-1 isolates. A marked down-regulation of both CD4 and CXCR4 expression was associated with this effect. Furthermore, a soluble factor(s) released by macrophages upon LPS treatment inhibited infection with CXCR4-tropic HIV-1 isolate viruses in both macrophages and T lymphocytes. Infection of both cell types appeared to be blocked at the level of viral entry and was independent of stromal cell-derived factor-1, the only known natural ligand of CXCR4. Moreover, the suppressive effect of LPS was unrelated to the release of IFN-alpha and -beta, macrophage-derived chemokine, leukemia inhibitory factor, or TNF-alpha. These results suggest the existence of potent HIV-1 inhibitory factor(s), uncharacterized to date, released by activated cells of the mononuclear phagocytic system.