Transient production of receptor-binding domain of SARS-CoV-2 in Nicotiana benthamiana plants induces specific antibodies in immunized mice.

BACKGROUND: The COVID-19 pandemic caused by the SARS-CoV-2 coronavirus has currently affected millions of people around the world. To combat the rapid spread of COVID-19 there is an urgent need to implement technological platforms for the production of vaccines, drugs and diagnostic systems by the scientific community and pharmaceutical companies. The SARS-CoV-2 virus enters the cells by the interaction between the receptor-binding domain (RBD) present in the viral surface spike protein and its human receptor ACE2. The RBD protein is therefore considered as the target for potential subunit-based vaccines. METHODS AND RESULTS: We evaluate the use of Nicotiana benthamiana plants as the host to transiently-producing recombinant RBD (RBDr) protein. The identity of the plant-produced RBDr was confirmed by immune assays and mass spectrometry. Immunogenicity was confirmed through the specific antibodies generated in all of the immunized mice compared to the PBS treated group. CONCLUSIONS: In conclusions, the immunogenicity of the RBDr produced in N. benthamiana was confirmed. These findings support the use of plants as an antigen expression system for the rapid development of vaccine candidates.

Willingness to receive COVID-19 vaccination in people living with HIV/AIDS from Latin America.

BACKGROUND: Prior research has established some risk factors for an increased risk of severe disease and mortality from coronavirus disease 2019 (COVID-19). However, the impact of HIV infection on SARS-CoV-2 susceptibility and severity is a significant gap in the literature. In the same way, not many studies across the globe have analyzed the degree of vaccination willingness among people living with HIV/AIDS (PLWHA) and considerations regarding prioritizing this population during vaccination plans, particularly in developing countries. METHODS: A descriptive-analytical cross-sectional study was conducted. Self-completed electronic surveys directed to PLWHA were performed via Twitter in February 2021, using accounts of HIV activists. RESULTS: 460 (87.1%) participants were willing to be vaccinated with any COVID-19 vaccine. The reasons for that were listed as 1) the belief that vaccination prevents both the COVID-19 infection (81.3%) as well as being a spreader (52.2%); 2) having a high occupational risk of becoming infected with COVID-19 (22%); and 3) the belief that they would be at high risk of death because of COVID-19 (21.3%). Only 56 (10.6%) participants expressed hesitancy toward vaccination, and 12 (2.2%) stated they did not want to get vaccinated. CONCLUSIONS: Our results may support the prioritization of people living with HIV during the implementation of vaccination plans in developing countries. New strategies should be adopted to overcome the hesitancy and unwillingness toward the COVID-19 vaccination, especially in populations with risk factors for severe disease.

Susceptibility for Some Infectious Diseases in Patients With Diabetes: The Key Role of Glycemia.

Uncontrolled diabetes results in several metabolic alterations including hyperglycemia. Indeed, several preclinical and clinical studies have suggested that this condition may induce susceptibility and the development of more aggressive infectious diseases, especially those caused by some bacteria (including Chlamydophila pneumoniae, Haemophilus influenzae, and Streptococcus pneumoniae, among others) and viruses [such as coronavirus 2 (CoV2), Influenza A virus, Hepatitis B, etc.]. Although the precise mechanisms that link glycemia to the exacerbated infections remain elusive, hyperglycemia is known to induce a wide array of changes in the immune system activity, including alterations in: (i) the microenvironment of immune cells (e.g., pH, blood viscosity and other biochemical parameters); (ii) the supply of energy to infectious bacteria; (iii) the inflammatory response; and (iv) oxidative stress as a result of bacterial proliferative metabolism. Consistent with this evidence, some bacterial infections are typical (and/or have a worse prognosis) in patients with hypercaloric diets and a stressful lifestyle (conditions that promote hyperglycemic episodes). On this basis, the present review is particularly focused on: (i) the role of diabetes in the development of some bacterial and viral infections by analyzing preclinical and clinical findings; (ii) discussing the possible mechanisms by which hyperglycemia may increase the susceptibility for developing infections; and (iii) further understanding the impact of hyperglycemia on the immune system.