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Foamy viruses are frequently found in non-human primates and apes in captivity. However, data on simian foamy virus (SFV) infection in apes from the wild are limited. Necropsy specimens were collected from 14 West African chimpanzees (Pan troglodytes verus) from three communities in the Taï National Park, Côte d'Ivoire. PCR analysis revealed SFV-related int- and env-specific sequences in 12/14 chimpanzees. Two young chimpanzees were not infected. Plasma from 'PCR-positive' chimpanzees reacted against Pr71/74(gag) in Western blot analysis. Phylogenetic analysis demonstrated clustering of all analysed sequences with SFVcpz previously identified from the other P. troglodytes verus, although interestingly the sequences were diverse and no grouping according to a particular animal community was observed. The body compartments of two infected animals were examined and found to contain SFV sequences. Frequent SFV infections in chimpanzees from this area significantly increase the potential risk of zoonotic transmission to rural populations through direct contact, hunting and consumption of bush meat.

The unusual resistance of agents causing transmissible spongiform encephalopathies (TSEs) to chemical or thermal inactivation requires special decontamination procedures in order to prevent accidental transmission of these pathogens by surgical instruments. In the search for effective, instrument-compatible and routinely applicable decontamination procedures, a previous study [Lemmer, K., Mielke, M., Pauli, G. & Beekes, M. (2004). J Gen Virol 85, 3805-3816] identified promising reagents in an in vitro carrier assay using steel wires contaminated with the disease-associated prion protein, PrP(Sc). In the follow-up study presented here, these reagents were validated for their decontamination potential in vivo. Steel wires initially loaded with >or=3 x 10(5) LD(50) of 263K scrapie infectivity were implanted into the brains of hamsters after treatment for decontamination and subsequently monitored for their potential to trigger clinical disease or subclinical cerebral PrP(Sc) deposition within an observation period of 500 days. It was found that routinely usable reagents such as a commercially available alkaline cleaner (pH 12.2) applied for 1 h at 23 degrees C or for 10 min at 55 degrees C and a mixture of 0.2 % SDS and 0.3 % NaOH (pH 12.8) applied for 5 or 10 min at 23 degrees C achieved removal of 263K scrapie infectivity below the threshold of detection (titre reduction of >or=5.5 log(10) units). The increasing use during the past few years of similar model systems by different research groups will facilitate comparison and integration of findings on the decontamination of steel surfaces from prions. Methods identified as highly effective in the 263K steel wire model need to be validated for human TSE agents on different types of instrument surfaces.

Effective reprocessing of surgical instruments ensuring elimination of inadvertent contamination with infectious agents causing transmissible spongiform encephalopathies (TSEs) is essential for the prevention of iatrogenic transmission of Creutzfeldt-Jakob disease (CJD) or its new variant (vCJD) from asymptomatic carriers. In a search for effective yet instrument-friendly and routinely applicable reprocessing procedures, we used an in vitro carrier assay to assess the decontamination activity exerted by different reagents on pathological prion protein (PrP(Sc)), the biochemical marker for TSE infectivity, attached to steel surfaces. In this assay, steel wires were contaminated with 263K scrapie brain homogenate and reprocessed for decontamination by exposure to several different test reagents. Residual contamination with PrP(Sc) and its protease-resistant core PrP27-30, still present after reprocessing on the wire surface or in the cleaning solution, was monitored by sensitive Western blot detection without or after proteinase K digestion. Using this approach, various reagents and processing conditions were screened for both their efficacy of decontamination and their active principles, such as detachment, destabilization or degradation of surface-bound prion protein. This revealed that, under appropriate conditions, relatively mild reagents such as 0.2 % SDS/0.3 % NaOH (pH 12.8), a commercially available alkaline cleaner (pH 11.9-12.2), a disinfectant containing 0.2 % peracetic acid and low concentrations of NaOH (pH 8.9) or 5 % SDS (pH 7.1) exert potent decontaminating activities on PrP(Sc)/PrP27-30 attached to steel surfaces. For in vivo validation, wires reprocessed in these reagents have been implanted into reporter animals in ongoing experiments.

Little information is available on the prevalence of retrovirus infections in populations of non-human primates living in their natural habitats. To gain such information, methods were developed to detect antibodies to simian T-lymphotropic virus type 1 (STLV-1) in urine from wild chimpanzees. Samples from more than 74 chimpanzees living in three communities in the Taï National Park, Côte d'Ivoire, were analysed. The prevalence of STLV-1 antibodies in adults and adolescents was significantly higher (35/49, 71.4 %) than that in infant and juvenile chimpanzees (3/31, 9.7 %).

Langerhans cells (LC), the dendritic antigen presenting cells of the skin, mature into potent immunostimulatory cells during migration to regional lymph nodes, where they are identified as interdigitating cells (IDC). Since mature Langerhans cells (mLC) resemble IDC in phenotype and immunostimulatory capacity, we examined whether these cells were susceptible to infection with macrophagetropic and lymphotropic strains of human immunodeficiency virus type 1 (HIV-1). Highly purified cell preparations of mLC migrating from human epidermis expressed high amounts of major histocompatibility complex (MHC) class I and II antigens and of the accessory molecules CD40, CD80 and CD86, indicative of the phenotype of potent immunostimulatory cells. CD4 expression was upregulated on mLC during cultivation, independent of the presence of tumour necrosis factor alpha (TNF-alpha) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in the culture medium. The macrophagetropic HIV-1 strain SF162 replicated to higher titres in mLC than the lymphotropic strain IIIB. Both strains induced syncytia, with SF162 showing a more rapid cytopathic effect. Addition of TNF-alpha enhanced virus production, due to better cell viability under TNF-alpha treatment, whereas GM-CSF did not significantly influence viability of cells and replication pattern of the virus. These findings suggest that in the infected individual IDC in lymph nodes may function as target cells for HIV-1.

Sequential overlapping Gag protein-derived oligopeptides of human immunodeficiency virus type 1 (HIV-1) 22 to 24 amino acids long, were synthesized and tested in vitro for antiviral activity. Two synthetic peptides, one derived from the matrix protein p17 (NPGLLETSEGCRQ, amino acids 47 to 59) and one located in the capsid protein p24 (PAATLEEMMTA, amino acids 339 to 349) inhibited the production of infectious virus when added to HIV-1-infected cultures when used in the range of 20 to 200 micrograms/ml. As shown by thin section electron microscopy, peptide treatment resulted in the release of immature, deformed virus particles suggesting that the two peptides interfered with assembly and maturation. Other Gag protein-derived oligopeptides had little or no influence on virus production. To characterize further the functionally active regions we synthesized peptide derivatives with three consecutive amino acids substituted by alanine; they did not cause inhibition. Therefore the regions responsible for inhibition were located between amino acids 50 to 61 in p17, and 342 to 350 in p24. These observations might lead to the development of a new antiviral strategy affecting the late stage of virus replication.

Monoclonal antibodies (MAbs) were raised against the glycoprotein gp120 of human immunodeficiency virus type 1 (strain HTLV-IIIB). The reactivity of five selected MAbs was characterized in several tests: ELISA, immunostaining of Western blots, immunofluorescence, immunoprecipitation, immunoelectron microscopy, alkaline phosphatase-anti-alkaline phosphatase assay and neutralization. The binding region was delimited by sequential overlapping Escherichia coli fusion proteins of the gp120 sequence between amino acids (aa) 49 and 280. In the ELISA, when using sequential overlapping 15 aa peptides, the binding epitopes were localized between aa 64 and 78 for three MAbs and between aa 114 and 123 for the fourth Mab. The fifth Mab showed multiple reactions with different peptides possibly indicating a reaction with a discontinuous epitope. In virus growth inhibition assays, all five MAbs inhibited the spread of HIV-1 infection in cell cultures after a single or repeated treatment at a concentration of 63 micrograms/ml of the purified MAbs. All MAbs showed low but significant neutralizing activity at concentrations of 100 micrograms/ml.

Monoclonal antibodies (MAbs) were raised against the transmembrane protein (TM) gp41 of human immunodeficiency virus type 1 (HIV-1, strain HTLV-IIIB). The reactivity of three TM-specific MAbs was investigated in several tests, ELISA, immunostaining of Western blots, immunofluorescence and an alkaline phosphatase-anti-alkaline phosphatase assay. Epitope mapping was done by using overlapping gp41 peptides produced as Escherichia coli fusion proteins and synthetic peptides. In an in vitro assay, all three MAbs showed enhancing effects on HIV-1 infection after single or repeated treatment with the purified MAbs at concentrations of 6 to 25 micrograms/ml. The enhancing domain is located between amino acids 724 and 752 of the env protein sequence. Homologous peptides based on this sequence were used for analysis of sera from 100 individuals at different stages of HIV infection to evaluate the relevance of antibodies against this region to the prognosis of disease. No antibodies reactive with this region were found in ELISA, indicating that this domain is not immunogenic in humans.

Monoclonal antibodies (MAbs) were raised against gag proteins of human immunodeficiency virus type 1 (HIV-1), strain HTLV-IIIB. One of 29 antibodies was specific for p17 of HIV-1. Twenty of 28 MAbs reactive with the major core protein p24 of HIV-1 showed cross-reactivity with HIV-2, and five of these also detected the corresponding antigens of simian immunodeficiency virus (SIVmac). The MAbs were reactive in several tests, i.e. ELISA, immunostaining of Western blots, immunofluorescence, alkaline phosphatase-anti-alkaline phosphatase immunocytochemistry and immunoelectron microscopy. The submembrane protein p17 was clearly localized within the virion.

The production and properties of monoclonal antibodies raised against herpes simplex virus type 1 (HSV-1)-infected cell nuclei are described. Biological and immunochemical assays revealed that these antibodies recognize four different proteins in HSV-1-infected cells. Four antibodies reacted with the major DNA-binding protein (ICP8) and six with the 65K DNA-binding protein. Two antibodies detected the ICP35 family of proteins and one antibody bound to a protein with an apparent mol. wt. of 60K. Immune electron microscopy showed that the major DNA-binding protein had a patchy distribution, whereas the 65K DNA-binding protein was evenly spread in the infected cell nuclei. The 60K protein as well as the polypeptides of the ICP35 family were preferentially found associated with the viral capsid.