Marwan Semaan

• PhD Student
• Robert Koch Institut

Xenotransplantation has been proposed as a solution to the shortage of suitable human donors for transplantation and pigs are currently favoured as donor animals. However, xenotransplantation may be associated with the transmission of zoonotic microorganisms. Whereas most porcine microorganisms representing a risk for the human recipient may be eli...

Background: To establish the safety of xenotransplantation when cells, tissues, or organs of pigs are used, an effective screening for potential zoonotic microorganisms has to be performed. In doing so, special attendance has to be paid to porcine endogenous retroviruses (PERVs) that are widely distributed as proviruses in the genome of pigs. PERV...

Estimation of the efficiency of the duplex real-time PCR specific for the new variant (nv) of PERV-C. Dilution of a specific nv PERV-C amplicon (efficiency 107 %), and of a cyclophilin plasmid (efficiency 115 %). (B) Real-time PCR analysis of three different pigs for investigating the presence of PERV-C, PERV-C new variant and porcine cyclophilin....

The transmembrane envelope protein gp41 of the human immunodeficiency virus HIV-1 plays an important role during infection allowing fusion of the viral and cellular membrane. In addition, there is increasing evidence that gp41 may contribute to the immunodeficiency induced by HIV-1. Recombinant gp41 and a synthetic peptide corresponding to a highly...

Absence of a correlation between the IL-6 release by PBMCs from 7 different donors and their SNP in the IL-10 promotor. Their PBMCs were incubated with the isu peptide homopolymer for 24 hrs at two different time point, the promoter of each donor was sequenced and the genetically expected IL-6 release is indicated. Donor B was not available at day...

Probes for the real-time RT-PCR analysis. (DOC)

Primers used for sequencing. (DOC)

Fifty cytokines with the highest increase in expression upon incubation of PBMCs with isu peptide polymers. The order is the result of a microarray comparing RNA from PBMCs incubated with the isu peptide homopolymer and from PBMCs incubated with medium. The expression of 27,000 genes was analysed. (DOCX)

Dependence of the Il-10 and IL-6 release on the donor PBMCs and the isu peptide polymer. A, PBMCs from one donor (A) was treated with 25 µg each of 3 different isu homopolymers (HP1-HP3), b, PBMCs from 9 donors (B to J) were treated with one and the same batch of an isu peptide homopolymer (HP4), c, PBMCs from one donor (L) was treated with 5 diffe...

Primers for the real-time RT-PCR analysis. (DOC)

Evolutionary conservation of the sequence of the isu domain. Human and simian immunodeficiency viruses were analysed, (.) marks identical amino acids, (*) marks deletions. Hatched amino acids represent conservative exchanges (A = S = T, I = L = M = V, R = K). (TIF)

Absence of a correlation between the IL-10 release by PBMCs from 7 different donors and their SNP in the IL-10 promotor. The PBMCs were incubated with the isu peptide homopolymer for 24 hrs at three different time points, the sequence of the relevant promoter region of each donor was determined and genetically expected IL-10 production is indicated...

Abbreviation and full names of the cytokines studied in the microarrays ( Table 1 ). (DOCX)

Fifty cytokines with the highest reduction in expression upon incubation of PBMCs with isu peptide polymers. The order is the result of a microarray comparing RNA from PBMCs incubated with the isu peptide homopolymer and from PBMCs incubated with medium. The expression of 27,000 genes was analysed. (DOCX)

Porcine endogenous retroviruses (PERV) are widely distributed in the genomes of pigs. PERV-A and PERV-B are present in all pigs. They infect human cells in vitro and therefore represent a risk for xenotransplantation when pig cells, tissues or organs are used. PERV-C infects only pig cells and is not present in the genomes of all pigs. However, PER...

The mechanism by which HIV-1 induces AIDS is still unknown. Previously, synthetic peptides corresponding to the conserved immunosuppressive (isu) domain in gp41 of HIV-1 had been shown to inhibit proliferation and to modulate cytokine expression of immune cells. The question is, whether the viral gp41 can do the same. We show for the first time tha...

Detection of non-glycosylated and glycosylated forms of wt gp41 and wt gp41ΔCT.(A) 293 T cells were transfected with the vector encoding wt gp41 (lane 1), and the backbone vector pcDNA3.1(−) as a negative control (lane 2). Cells were lysed 48 hours later, and proteins were examined by Western blot analysis. Non-glycosylated (p35) and glycosylated (...

Induction of IL-10 release by wt gp41 and wt gp41ΔCT and mutations in the isu domain abrogating IL-10 release. Cytokine release was studied in PBMCs of donor 2 after exposure to wt gp41ΔCT, wt gp41 and gp41 with mutations 1A, 2A. The mock control comes from the supernatant of cells transfected with the empty vector. P values were estimated in compa...

Statistical significance of the IL-10 release from PBMCs of each of the four donors (A) and of the IL-6 release from PBMCs of donor 4 (B) as shown in Figure3. The P values were estimated in comparison to the wt gp41.

List of the primers and probes used for real-time PCR.

Statistical significance of the IL-10 release (A) and of the transcriptional activation of IL-6 (B), MMP-1 (C) and FCN1 (D) as shown in Figure4. P values were estimated in comparison to wt gp41.

Porcine endogenous retroviruses (PERVs) represent a risk of xenotransplantation using porcine cells, tissues, or organs, as they are integrated in the porcine genome and have been shown to be able to infect human cells in vitro. To increase viral safety by RNA interference, transgenic pigs expressing a PERV-specific small hairpin (sh)RNA targeted t...

RNA interference (RNAi) is a RNA-dependent gene silencing process, which is initiated by small interfering (si) RNA and is controlled by the RNA induced silencing complex (RISC). Single strands of the siRNA are integrated into the activated RISC, they base-pair with the template RNA and induce cleavage of this mRNA, thereby preventing translation....