Browsing by Author "Ramirez, Mario A."

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    A molecular perspective for the development of antibodies against the human respiratory syncytial virus
    (2024) Loaiza, Ricardo A.; Ramirez, Robinson A.; Sepulveda-Alfaro, Javiera; Ramirez, Mario A.; Andrade, Catalina A.; Soto, Jorge A.; Gonzalez, Pablo A.; Bueno, Susan M.; Kalergis, Alexis M.
    The human respiratory syncytial virus (hRSV) is the leading etiologic agent causing respiratory infections in infants, children, older adults, and patients with comorbidities. Sixty-seven years have passed since the discovery of hRSV, and only a few successful mitigation or treatment tools have been developed against this virus. One of these is immunotherapy with monoclonal antibodies against structural proteins of the virus, such as Palivizumab, the first prophylactic approach approved by the Food and Drug Administration (FDA) of the USA. In this article, we discuss different strategies for the prevention and treatment of hRSV infection, focusing on the molecular mechanisms against each target that underly the rational design of antibodies against hRSV. At the same time, we describe the latest results regarding currently approved therapies against hRSV and the challenges associated with developing new candidates.
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    Co-administration of recombinant BCG and SARS-CoV-2 proteins leads to robust antiviral immunity
    (2024) Ramirez, Mario A.; Loaiza, Ricardo A.; Martinez-Balboa, Yohana; Bruneau, Nicole; Ramirez, Eugenio; Gonzalez, Pablo A.; Bueno, Susan M.; Kalergis, Alexis M.
    SARS-CoV-2 is the causative virus of COVID-19, which has been responsible for millions of deaths worldwide since its discovery. After its emergence, several variants have been identified that challenge the efficacy of the available vaccines. Previously, we generated and evaluated a vaccine based on a recombinant Bacillus Calmette-Gu & eacute;rin (rBCG) expressing the nucleoprotein (N) of SARS-CoV-2 (rBCG-N-SARS-CoV-2). This protein is a highly immunogenic antigen and well conserved among variants. Here, we tested the administration of this vaccine with recombinant N and viral Spike proteins (S), or Receptor Binding Domain (RBD-Omicron variant), plus a booster with the recombinant proteins only, as a novel and effective strategy to protect against SARS-CoV-2 variants. Methods: BALB/c mice were immunized with rBCG-N-SARS-CoV-2 and recombinant SARS-CoV-2 proteins in Alum adjuvant, followed by a booster with recombinant proteins to assess the safety and virus-specific cellular and humoral immune responses against SARS-CoV-2 antigens. Results: Immunization with rBCG-N-SARS-CoV-2 + recombinant proteins as a vaccine was safe and promoted the activation of CD4(+) and CD8(+) T cells that recognize SARS-CoV-2 N, S, and RBD antigens. These cells were able to secrete cytokines with an antiviral profile. This immunization strategy also induced robust titers of specific antibodies against N, S, and RBD and neutralizing antibodies of SARS-CoV-2. Conclusions: Co-administration of the rBCG-N-SARS-CoV-2 vaccine with recombinant SARS-CoV-2 proteins could be an effective alternative to control particular SARS-CoV-2 variants. Due to its safety and capacity to induce virus-specific immune responses, we believe the rBCG-N-SARS-CoV-2 + Proteins vaccine could be an attractive candidate to protect against this virus, especially in newborns.