SARS-CoV-2 RBD-Tetanus Toxoid Conjugate Vaccine Induces a Strong Neutralizing Immunity in Preclinical Studies.

Controlling the global COVID-19 pandemic depends, among other measures, on developing preventive vaccines at an unprecedented pace. Vaccines approved for use and those in development intend to elicit neutralizing antibodies to block viral sites binding to the host's cellular receptors. Virus infection is mediated by the spike glycoprotein trimer on the virion surface via its receptor binding domain (RBD). Antibody response to this domain is an important outcome of immunization and correlates well with viral neutralization. Here, we show that macromolecular constructs with recombinant RBD conjugated to tetanus toxoid (TT) induce a potent immune response in laboratory animals. Some advantages of immunization with RBD-TT conjugates include a predominant IgG immune response due to affinity maturation and long-term specific B-memory cells. These result demonstrate the potential of the conjugate COVID-19 vaccine candidates and enable their advance to clinical evaluation under the name SOBERANA02, paving the way for other antiviral conjugate vaccines.

National survey of pre-treatment HIV drug resistance in Cuban patients.

BACKGROUND: The World Health Organization (WHO) recommends a method to estimate nationally representative pretreatment HIV drug resistance (PDR) in order to evaluate the effectiveness of first -line treatments. The objective of the present study was to determine the prevalence of PDR in Cuban adults infected with HIV-1. MATERIALS AND METHODS: A cross-sectional study in Cuban adults infected with HIV-1 over 18 years was conducted. The probability proportional to size method for the selection of municipalities and patients without a prior history of antiretroviral treatment during the period from January 2017 to June 2017 was used. The plasma from 141 patients from 15 municipalities for the determination of viral subtype and HIV drug resistance was collected. Some clinical and epidemiological variables were evaluated. RESULTS: 80. 9% of the patients corresponded to the male sex and 76.3% were men who have sex with other men (MSM). The median CD4 count was 371 cells / mm3 and the median viral load was 68000 copies / mL. The predominant genetic variants were subtype B (26.9%), CRF19_cpx (24.1%), CRF 20, 23, 24_BG (23.4%) and CRF18_cpx (12%). Overall, the prevalence of PDR was 29.8% (95%, CI 22.3-38.1). The prevalence was 12.8% (95%, CI 6.07-16.9) for any nucleoside reverse transcriptase inhibitor (NRTI), 23.4% (95%, CI 16.7-31.3) for any non-reverse transcriptase inhibitor (NNRTI) and 1.4% (95%, CI 0.17-5.03) for any protease inhibitor (PI). The most frequent mutations detected were K103N (12.9%), G190A (6.4%) and Y181C (4.8%). CONCLUSIONS: The NNRTI prevalence above 10% in our study indicates that the first-line antiretroviral therapy in Cuba may be less effective and supports the need to look for new treatment options that contribute to therapeutic success and help the country achieve the global goals 90-90-90 set forth by UNAIDS.

Identification of Vimentin as a Potential Therapeutic Target against HIV Infection.

A combination of antiviral drugs known as antiretroviral therapy (ART) has shown effectiveness against the human immunodeficiency virus (HIV). ART has markedly decreased mortality and morbidity among HIV-infected patients, having even reduced HIV transmission. However, an important current disadvantage, resistance development, remains to be solved. Hope is focused on developing drugs against cellular targets. This strategy is expected to prevent the emergence of viral resistance. In this study, using a comparative proteomic approach in MT4 cells treated with an anti-HIV leukocyte extract, we identified vimentin, a molecule forming intermediate filaments in the cell, as a possible target against HIV infection. We demonstrated a strong reduction of an HIV-1 based lentivirus expressing the enhanced green fluorescent protein (eGFP) in vimentin knockdown cells, and a noteworthy decrease of HIV-1 capsid protein antigen (CAp24) in those cells using a multiround infectivity assay. Electron micrographs showed changes in the structure of intermediate filaments when MT4 cells were treated with an anti-HIV leukocyte extract. Changes in the structure of intermediate filaments were also observed in vimentin knockdown MT4 cells. A synthetic peptide derived from a cytoskeleton protein showed potent inhibitory activity on HIV-1 infection, and low cytotoxicity. Our data suggest that vimentin can be a suitable target to inhibit HIV-1.

Phylogenetic analysis of human immunodeficiency virus type 2 isolated from Cuban individuals.

The presence of infection by human immunodeficiency virus type 2 (HIV-2) in Cuba has been previously documented. However, genetic information on the strains that circulate in the Cuban people is still unknown. The present work constitutes the first study concerning the phylogenetic relationship of HIV-2 Cuban isolates conducted on 13 Cuban patients who were diagnosed with HIV-2. The env sequences were analyzed for the construction of a phylogenetic tree with reference sequences of HIV-2. Phylogenetic analysis of the env gene showed that all the Cuban sequences clustered in group A of HIV-2. The analysis indicated several independent introductions of HIV-2 into Cuba. The results of the study will reinforce the program on the epidemiological surveillance of the infection in Cuba and make possible further molecular evolutionary studies.

Safety of the production process of SURFACEN(®) to inactivate and remove virus.

SURFACEN(®) is a biological product produced from pig lungs. Since these animals can be potential sources of microbial pathogens such as viruses, the manufacturing process of this product should guarantee safety from health hazards. The SURFACEN(®) production procedure is capable of effective viral clearance (inactivation/removal) by involving two stages of organic solvent extraction followed by acetone precipitation and heat treatment. In this study, we evaluated the clearance capacity of these four stages for a wide range of viruses by performing spiking experiments. Residual contamination was assessed using a Tissue Culture Infectious Dose assay (log10 TCID50). The validation study demonstrated that, for all viruses tested, the TCID50 titers were reduced by more than 2 log10 in each stage. Total log reduction values achieved were between ≥17.82 log10 and ≥27.93 log10, depending on the virus physical properties, titer, and the number of processing stages applied. Results indicated that the production procedure of SURFACEN(®) can inactivate or remove contaminant viruses from the raw material.

Validation of model virus removal and inactivation capacity of an erythropoietin purification process.

Human erythropoietin (hEpo) production requires mammalian cells able to make complex post-translational modifications to guaranty its biological activity. As mammalian cell can be reservoir of pathogenic viruses and several animal origin components are usually used in the cultivation of mammalian cells, hEpo contamination with viruses is something of great concern. As consequence, this study investigated the viral removal and inactivation capacity of a recombinant-hEpo (rec-hEpo) purification process. Canine parvovirus, Human poliovirus type-2, Bovine viral diarrhea virus and Human immunodeficiency virus type-1 were used for measuring process viral removal and inactivation capacities. In conclusion, this study corroborated that the assessed rec-hEpo purification process has enough capacity (5.0-19.4 Logs) for removing and inactivating these model viruses and sodium hydroxide demonstrated to be a robust sanitization solution for chromatography columns (5.0 (PV-2)-6.7 (CPV) Logs).

High HIV-1 genetic diversity in Cuba.

BACKGROUND: HIV-1 subtype B is largely predominant in the Caribbean, although other subtypes have been recently identified in Cuba. OBJECTIVES: To examine HIV-1 genetic diversity in Cuba. METHODS: The study enrolled 105 HIV-1-infected individuals, 93 of whom had acquired the infection in Cuba. DNA from peripheral blood mononuclear cells was used for polymerase chain reaction amplification and sequencing of pol (protease-reverse transcriptase) and env (V3 region) segments. Phylogenetic trees were constructed using the neighbour-joining method. Intersubtype recombination was analysed by bootscanning. RESULTS: Of the samples, 50 (48%) were of subtype B and 55 (52%) of diverse non-B subtypes and recombinant forms. Among non-B viruses, 12 were non-recombinant, belonging to six subtypes (C, D, F1, G, H and J), the most frequent of which was subtype G (n = 5). The remaining 43 (78%) non-B viruses were recombinant, with 14 different forms, the two most common of which were Dpol/Aenv (n = 21) and U(unknown)pol/Henv (n = 7), which grouped in respective monophyletic clusters. Twelve recombinant viruses were mosaics of different genetic forms circulating in Cuba. Overall, 21 genetic forms were identified, with all known HIV-1 group M subtypes present in Cuba, either as non-recombinant viruses or as segments of recombinant forms. Non-B subtype viruses were predominant among heterosexuals (72%) and B subtype viruses among homo- or bisexuals (63%). CONCLUSION: An extraordinarily high diversity of HIV-1 genetic forms, unparalleled in the Americas and comparable to that found in Central Africa, is present in Cuba.