Browsing by Author "Soto, Jorge"

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    Cellular immune response induced by surface immunogenic protein with AbISCO-100 adjuvant vaccination decreases group B Streptococcus vaginal colonization.
    (Elsevier Ltd, 2019) Soto, Jorge; Diaz-Dinamarca, Diego; Soto, Daniel; Barrientos, Magaly; Carrión, Flavio; Kalergis, Alexis; Vásquez, Abel
    Group B Streptococcus (GBS) represents one of the most common causes of bacterial infection in neonates; it is also associated with premature childbirth and stillbirth. A vaccine against GBS is needed, but no approved vaccines are yet available. The Surface Immunogenic Protein (SIP) of GBS is conserved in all serotypes and had been reported to be a good vaccine prototype in a mouse model of GBS infection. Also, we have previously shown that both subcutaneous and oral immunization with rSIP can induce an efficient immune response that decreases GBS vaginal colonization in mice. In this study, we show that a vaccine based on a mixture of rSIP and AbISCO-100 adjuvant reduces GBS vaginal colonization in mice and induces antibodies with opsonophagocytic activities. Moreover, the passive transfer of sera and total T-cells from mice immunized with rSIP mixed with AbISCO-100 to unvaccinated mice decreases vaginal GBS colonization in an infected mouse. This is the first report of cellular immunity associated with rSIP-based vaccine testing in a mouse model of GBS infection.
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    Inactivated Vaccine-Induced SARS-CoV-2 Variant-Specific Immunity in Children
    (2022) Soto, Jorge; Melo, Felipe; Gutierrez, Cristián; Schultz, Bárbara; Berríos, Roslye; Rivera, Daniela; Piña, Alejandro; Hoppe, Guillermo; Duarte, Luisa; Vázquez, Yaneisi; Moreno, Daniela; Ríos, Mariana; Palacios, Pablo; Garcia, Richard; Santibañez, Álvaro; Pacheco, Gaspar; Mendez, Constanza; Andrade, Catalina; Silva, Pedro; Diethelm, Benjamín; Astudillo, Patricio; Calvo, Mario; Cárdenas, Antonio; González, Marcela; Goldsack, Macarena; Gutiérrez, Valentina; Potin, Marcela; Schilling, Andrea; Tapia, Lorena; Twele, Loreto; Villena, Rodolfo; Grifoni, Alba; Sette, Alessandro; Weiskopf, Daniela; Fasce, Rodrigo; Fernández, Jorge; Mora, Judith; Ramírez, Eugenio; Gaete, Aracelly; Acevedo, Mónica; Valiente, Fernando; Soto, Ricardo; Retamal, Angello; Muñoz, Nathalia; PedCoronaVac03CL Study Group; Meng, Xing; Xin, Qianqian; Alarcón, Eduardo; González, José; Le Corre, Nicole; Álvarez, María; González, Pablo; Abarca, Katia; Perret, Cecilia; Carreño, Leandro; Bueno, Susan; Kalergisa, Alexis
    Multiple vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been evaluated in clinical trials. However, trials addressing the immune response in the pediatric population are scarce. The inactivated vaccine CoronaVac has been shown to be safe and immunogenic in a phase 1/2 clinical trial in a pediatric cohort in China. Here, we report interim safety and immunogenicity results of a phase 3 clinical trial for CoronaVac in healthy children and adolescents in Chile. Participants 3 to 17 years old received two doses of CoronaVac in a 4-week interval until 31 December 2021. Local and systemic adverse reactions were registered for volunteers who received one or two doses of CoronaVac. Whole-blood samples were collected from a subgroup of 148 participants for humoral and cellular immunity analyses. The main adverse reaction reported after the first and second doses was pain at the injection site. Four weeks after the second dose, an increase in neutralizing antibody titer was observed in subjects relative to their baseline visit. Similar results were found for activation of specific CD4+ T cells. Neutralizing antibodies were identified against the Delta and Omicron variants. However, these titers were lower than those for the D614G strain. Importantly, comparable CD4+ T cell responses were detected against these variants of concern. Therefore, CoronaVac is safe and immunogenic in subjects 3 to 17 years old, inducing neutralizing antibody secretion and activating CD4+ T cells against SARS-CoV-2 and its variants. (This study has been registered at ClinicalTrials.gov under no. NCT04992260.) IMPORTANCE This work evaluated the immune response induced by two doses of CoronaVac separated by 4 weeks in healthy children and adolescents in Chile. To date, few studies have described the effects of CoronaVac in the pediatric population. Therefore, it is essential to generate knowledge regarding the protection of vaccines in this population. Along these lines, we reported the anti-S humoral response and cellular immune response to several SARS-CoV-2 proteins that have been published and recently studied. Here, we show that a vaccination schedule consisting of two doses separated by 4 weeks induces the secretion of neutralizing antibodies against SARS-CoV-2. Furthermore, CoronaVac induces the activation of CD4+ T cells upon stimulation with peptides from the proteome of SARS-CoV-2. These results indicate that, even though the neutralizing antibody response induced by vaccination decreases against the Delta and Omicron variants, the cellular response against these variants is comparable to the response against the ancestral strain D614G, even being significantly higher against Omicron.

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