Molecular modelling on multiepitope-based vaccine against SARS-CoV-2 using immunoinformatics, molecular docking, and molecular dynamics simulation.

The pandemic of COVID-19 caused by SARS-CoV-2 has made a worldwide health emergency. Despite the fact that current vaccines are readily available, several SARSCoV-2 variants affecting the existing vaccine are to be less effective due to the mutations in the structural proteins. Furthermore, the appearance of the new variants cannot be easily predicted in the future. Therefore, the attempts to construct new vaccines or to modify the current vaccines are still pivotal works for preventing the spread of the virus. In the present investigation, the computational analysis through immunoinformatics, molecular docking, and molecular dynamics (MD) simulation is employed to construct an effective vaccine against SARS-CoV2. The structural proteins of SARS-CoV2 are utilized to create a multiepitope-based vaccine (MEV). According to our findings presented by systematic procedures in the current investigation, the MEV construct may be able to trigger a strong immunological response against the virus. Therefore, the designed MEV could be a potential vaccine candidate against SARS-CoV-2, and also it is expected to be effective for other variants.

Molecular modelling on SARS-CoV-2 papain-like protease: an integrated study with homology modelling, molecular docking, and molecular dynamics simulations.

SARS-CoV-2 PLpro was investigated as a therapeutic target for potent antiviral drugs due to its essential role in not only viral replication but also in regulating the inborn immune response. Several computational approaches, including homology modelling, molecular docking, and molecular dynamics (MD) studies, were employed to search for promising drugs in treating SARS-CoV-2. Eighty-one compounds, sub-structurally similar to the antiviral drug, were used as potential inhibitors of PLpro. From our results, three complexes containing the ligands with Pubchem IDs: 153012995, 12149203, and 123608715 showed lower binding energies than the control (Ritonavir), indicating that they may become promising inhibitors for PLpro. MD was performed in a water solvent to validate the stability of the three complexes. All complexes achieved stable structure during the simulation as no significant fluctuations were observed in the validation parameters. Moreover, the binding energy for each complex was estimated using the MM-GBSA method. Complex 1 was the most stable structure based on the lowest binding energy score and its structure remained in a similar cavity with the docket snapshot. Based on our studies, three ligands were assumed to be potential inhibitors. The ligand of complex 1 may become the most promising antiviral drug against SARS-CoV-2 targeting PLpro.

[Multiple facial nodules revealing disseminated cryptococcosis in an immunocompetent patient]. / Nodules multiples du visage révélant une cryptococcose disséminée chez un patient immunocompétent.

BACKGROUND: Cryptococcosis is a potentially severe infection that usually occurs in a setting of immunosuppression. Its occurrence outside of this context is rare. We report a case of disseminated cryptococcosis revealed by a spectacular skin disease in an immunocompetent patient. PATIENTS AND METHODS: A 40-year-old male patient had been presenting multiple nodules and tumors on his face for one month in a context of asthenia and intermittent fever. Histological examination of a skin biopsy revealed encapsulated yeasts strongly suggestive of Cryptococcus neoformans. Mycological examination of the skin biopsy and cerebrospinal fluid isolated Cryptococcus gattii. The blood cultures were positive. Brain MRI demonstrated cryptococcal parenchymal involvement. Screening for primary or secondary immunodeficiency was negative. The patient received amphotericin B 1mg/kg/day and fluconazole 600mg/day but died 2months after diagnosis. DISCUSSION: Cryptococcosis is a potentially severe infection caused by C. neoformans. This rare condition occurs most commonly in patients with profound deficiency in terms of cellular immunity. Although rare, the occurrence of cryptococcosis in immunocompetent patients is possible, and in this event the signs are highly polymorphic, which usually makes it very difficult to diagnose. The diagnosis of cryptococcosis is based on the identification by direct examination and after staining with India ink of encapsulated yeasts of the Cryptococcus genus. Culture on Sabouraud medium is essential for identification of the species. Treatment for disseminated cryptococcosis involves amphotericin B, often associated with flucytosine IV. In the event of meningitis infection in non-HIV patients, mortality continues to be around 15%, despite adequate medical treatment. CONCLUSION: Although rare, cryptococcosis can occur in immunocompetent subjects. The prognosis is severe even after treatment.

[Recurrence of cutaneous sarcoidosis during immune reconstitution syndrome in an HIV-infected patient]. / Récidive de sarcoïdose cutanée lors du syndrome de restauration immunitaire chez une patiente infectée par le VIH.

BACKGROUND: Association of sarcoidosis and HIV can occur in the context of immune reconstitution syndrome (IRS) after initiation of antiretroviral therapy (ART). Herein we report a case of cutaneous sarcoidosis in remission in an HIV-infected patient but relapsing during IRS associated with initiation of ART. PATIENTS AND METHODS: A 33-year-old female HIV-infected patient from Cameroon was treated with triple therapy with good efficacy. The patient previously had a small nodular lesion on her left cheek which disappeared spontaneously 2 months before the diagnosis of HIV infection. Three months after initiation of triple ART, the patient consulted again for recurrence of the lesion, which had gradually increased in size. Clinical examination revealed a purplish-red nodular plaque of lupoid appearance under vitropression, located between the inner corner of the eye, the nasal wing and the left cheek. A skin biopsy revealed giant-cell epithelioid dermal granulomas without caseous necrosis. Blood angiotensin-converting enzyme levels were elevated and intradermal reaction to tuberculin was negative. A diagnosis was made of cutaneous sarcoidosis. The patient was treated with chloroquine 200mg/day for 3 months, resulting in total subsidence of the lesions. No recurrence was observed at 1 year. DISCUSSION: Introduction of ART has changed the dermatological aspect of HIV infection. In addition to specific dermatological signs specific to HIV and to immunosuppression, there are the cutaneous adverse effects of antiretroviral drugs and skin disorders indicating reconstituted immunity during IRS. Schematically, three forms of IRS may be distinguished: the paradoxical form, the infectious form, and the inflammatory form. The latter corresponds to the onset or exacerbation of inflammatory conditions or autoimmune diseases after the start of ART. Thirty cases of association between sarcoidosis and HIV have been described, of which two-thirds occurred during IRS. The central role of CD4 in sarcoidosis explains its occurrence in HIV patients during reconstitution of the CD4 count. CONCLUSION: In HIV-infected patients treated with anti-retroviral treatment, certain skin diseases such as sarcoidosis may be related to IRS.

[Extensive ulcerations in children: The difficulty diagnosing pyoderma gangrenosum]. / Ulcérations extensives chez l'enfant : penser au pyoderma gangrenosum.

Pyoderma gangrenosum is an amicrobial neutrophilic dermatosis of unknown cause with a chronic course. We report a case in a 30-month-old child who presented with progressive and painful skin ulcers. Lesions were quickly extensive, refractory to local and systemic antibiotic therapy. Histopathology of the skin biopsies confirmed the diagnosis of ulcerative pyoderma gangrenosum. Only 4% of the cases reported in the literature are in children below the age of 4 years. This neutrophilic dermatosis is associated in half of the cases with a systemic disease. The treatment is based on corticosteroids. Immunosuppressant drugs such as tacrolimus, cyclosporine, and mycophenolate mofetil may be effective for pyoderma gangrenosum refractory to corticosteroids. Currently, anti-TNF is a promising treatment for refractory PG.

[Demonstration of the Leishmanicidal activity of Stachys guyoniana against Leishmania major in eastern Algeria]. / Mise en évidence de l'activité antileishmanienne de Stachys guyoniana contre Leishmania major dans l'Est algérien.

The authors report the results of the assessment of the Leishmanicidal activity of a plant species of the Lamiaceae family, Stachys guyoniana. This in vitro study used the species endemic in Algeria, Leishmania major. Both the butanolic and ethyl acetate extracts showed strong activity against this strain.

p-O-geranylcoumaric acid from Melicope lunu-ankenda.

Leaf extracts of Melicope lunu-ankenda were chemically studied and found to contain mixtures of hydrocarbons and squalene, fatty acids and esters. A geranylated coumaric acid was isolated as the major compound. The crude dichloromethane and methanol extracts of the leaves were found to be strongly larvicidal with LC50 values below 20 microg mL(-1). This is a first isolation of p-O-geranylcoumaric acid from this plant.