Papers by Nasreddine SAIDI
Frontiers in Immunology
Cutaneous leishmaniasis (CL) caused by infection with the parasite Leishmania exhibits a large sp... more Cutaneous leishmaniasis (CL) caused by infection with the parasite Leishmania exhibits a large spectrum of clinical manifestations ranging from single healing to severe chronic lesions with the manifestation of resistance or not to treatment. Depending on the specie and multiple environmental parameters, the evolution of lesions is determined by a complex interaction between parasite factors and the early immune responses triggered, including innate and adaptive mechanisms. Moreover, lesion resolution requires parasite control as well as modulation of the pathologic local inflammation responses and the initiation of wound healing responses. Here, we have summarized recent advances in understanding the in situ immune response to cutaneous leishmaniasis: i) in North Africa caused by Leishmania (L.) major, L. tropica, and L. infantum, which caused in most cases localized autoresolutives forms, and ii) in French Guiana resulting from L. guyanensis and L. braziliensis, two of the most pr...
Immunol Lett , 2023
• Co-infection of SARS-CoV-2 and visceral or cutaneous leishmaniasis may lead to changes in susce... more • Co-infection of SARS-CoV-2 and visceral or cutaneous leishmaniasis may lead to changes in susceptibility and/or severity of COVID-19.
•IFN-γ- responses to Leishmania could play a role in controlling SARS-CoV-2.
•Parasitic neglected tropical diseases (NTDs) can alter the immunologic responses to SARS-CoV-2.
Microorganisms
Leishmania major cutaneous leishmaniasis (CL) lesions are characterized by an intense process of ... more Leishmania major cutaneous leishmaniasis (CL) lesions are characterized by an intense process of parasite destruction and antigen processing that could limit microscopic amastigote detection. The aim of our study was to develop a direct immunofluorescence (DIF) assay for in situ visualization of L. major antigens and access its reliability in the routine diagnosis of CL. The developed DIF assay used IgG polyclonal antibodies produced in rabbits by intravenous injections of live L. major metacyclic promastigotes chemically coupled to fluorescein isothiocyanate. Applied to L. major infected RAW macrophages, corresponding macrophage-derived amastigotes and dermal scrapings from CL lesions, the immunofluorescence assay stained specifically Leishmania amastigotes and showed a diffuse Leishmania antigen deposit into cytoplasm of phagocytic cells. Reliability of DIF in CL diagnosis was assessed on 101 methanol-fixed dermal smears from 59 positive and 42 negative CL lesions diagnosed by dir...
Frontiers in Genetics
Background: Colorectal cancer (CRC) is a major public health problem worldwide and in Tunisia. It... more Background: Colorectal cancer (CRC) is a major public health problem worldwide and in Tunisia. It ranks among the main cancers in terms of incidence and cancer-related cause of death. Its pathogenesis is currently considered to be multifactorial involving genetic and environmental factors. Recent studies have suggested that the gene encoding the β1 subunit of the IL-12 receptor, an important pro-inflammatory cytokine of the anti-tumor response, could be involved in the susceptibility to inherited CRC. Hence, it would be interesting to study the role of single nucleotide polymorphisms (SNPs) within the IL-12RB1 gene (rs401502 and rs11575934) in CRC susceptibility.Aim: Our purpose was to assess whether genetic variants IL-12RB1 +1196G/C (rs401502) and IL-12RB1 +705A/G (rs11575934) within the IL-12RB1 gene are associated with the sporadic CRC risk.Methods: A total of 110 Tunisian patients with sporadic CRC and 141 healthy control subjects were included in this study. Genotyping was per...
Frontiers in Genetics, 2021
Background and objectives: Human cytomegalovirus (HCMV) and genetic polymorphisms of the chemokin... more Background and objectives: Human cytomegalovirus (HCMV) and genetic polymorphisms of the chemokine receptor 5 have been suggested as factors associated with the progression of colorectal cancer (CRC). The aim of the study was to evaluate the associations of both CCR5Δ32 genetic deletion and/or HCMV virus infection with CRC in Tunisia. Materials and methods: The association between HCMV and CRC was validated by Nested PCR technology performed for HCMV and HCMV-specific serum IgG and IgM antibodies were investigated by enzyme-linked immunosorbent assay. Experiments were carried out on 40 tumor and 35 peri-tumor tissues, 100 blood from CRC patients and on 140 blood samples from healthy subjects and finaly serum samples of 80 patients with CRC and 100 healthy individuals. A conventional PCR has been optimized for the detection of CCR5Δ32 in100 CRC patients and 100 healthy subjects. Results: Our results show that HCMV is significantly active in 93% of patients compared to 60% in controls...
Acta Tropica, 2021
Immunomagnetic Separation (IMS) assay has been used for isolation of viable whole organisms. The ... more Immunomagnetic Separation (IMS) assay has been used for isolation of viable whole organisms. The objective of our work is to produce anti-Leishmania magnetic beads and to assess the efficiency of the IMS technique on Leishmania promastigote capture in culture media. Polyclonal anti-Leishmania antibodies were produced by intravenous injection of viable metacyclic promastigotes of Leishmania (L.) major to rabbit. Purified anti-Leishmania IgG was assessed for their reactivity against both L. major and L. infantum promastigotes then covalently conjugated to magnetic beads and used for IMS. This latter was applied on either L. major promastigote cultures of known concentrations or early stage (24h, 48h, 72h) Novy-MacNeal-Nicolle (NNN) cultures of tissue fluid obtained from cutaneous leishmaniasis (CL) lesions. Promastigotes capture was assessed by either microscopy or qPCR after sample boiling. Indirect immunofluorescence assay showed that polyclonal antibodies reacted against both L. major and L. infantum promastigotes. In 50 µL solution, immunomagnetic beads were able to capture 5 live promastigotes out of 20 and 1050 out of 2500, giving an estimated efficiency of 25-42%. The efficiency of the IMS was lower for a lower number of parasites but still repeatable. On the other hand, IMS-qPCR applied to 14 NNN cultures of confirmed Leishmania lesions showed a higher sensitivity to detect live parasites than routine microscopy observation of promastigotes growth (93% positivity at 72h versus 50% positivity within 2-4 weeks incubation). The estimated number of captured parasites at 72h ranged from 1 to more than 100 parasites / 50 µL liquid phase of culture. These preliminary results open the way for interesting perspectives in the use of cultures for leishmaniasis diagnosis and also for other applications such as Leishmania detection in sandflies.
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Papers by Nasreddine SAIDI
•IFN-γ- responses to Leishmania could play a role in controlling SARS-CoV-2.
•Parasitic neglected tropical diseases (NTDs) can alter the immunologic responses to SARS-CoV-2.
•IFN-γ- responses to Leishmania could play a role in controlling SARS-CoV-2.
•Parasitic neglected tropical diseases (NTDs) can alter the immunologic responses to SARS-CoV-2.