SARS-CoV-2 recombinant proteins stimulate distinct cellular and humoral immune response profiles in samples from COVID-19 convalescent patients

OBJECTIVES: In this preliminary study we investigated cellular and humoral immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in blood samples from 14 recovered coronavirus disease 2019 (COVID-19) patients and compared them to those in samples from 12 uninfected/unvaccinated volunteers. METHODS: Cellular immunity was assessed by intracellular detection of IFN-γ in CD3+ T lymphocytes after stimulation with SARS-CoV-2 spike (S1), nucleocapsid (NC), or receptor-binding domain (RBD) recombinant proteins or overlapping peptide pools covering the sequence of SARS-CoV-2 spike, membrane and nucleocapsid regions. The humoral response was examined by ELISAs and/or chemiluminescence assays for the presence of serum IgG antibodies directed to SARS-CoV-2 proteins. RESULTS: We observed differences between humoral and cellular immune profiles in response to stimulation with the same proteins. Assays of IgG antibodies directed to SARS-CoV-2 NC, RBD and S1/S2 recombinant proteins were able to differentiate convalescent from uninfected/unvaccinated groups. Cellular immune responses to SARS-CoV-2 protein stimuli did not exhibit a specific response, as T cells from both individuals with no history of contact with SARS-CoV-2 and from recovered donors were able to produce IFN-γ. CONCLUSIONS: Determination of the cellular immune response to stimulation with a pool of SARS-CoV-2 peptides but not with SARS-CoV-2 proteins is able to distinguish convalescent individuals from unexposed individuals. Regarding the humoral immune response, the screening for serum IgG antibodies directed to SARS-CoV-2 proteins has been shown to be specific for the response of recovered individuals.

Displasia de quadril em áreas endêmicas / Hip dysplasia in endemic regions

Os autores relatam os resultados observados em pesquisa de D.Q., realizada em uma populaçao de 517 R.N. da Maternidade de HEUCS, no período de outubro de 1991 até maio de 1992, com o intuito de comprovar a suspeita de que a populaçao de Caxias do Sul poderia ser mais afetada em virtude de ser, na sua maioria, integrada por descendentes de habitantes de uma área dita endêmica. Foram detectadas D.Q. em 3 dos 517 R.N. (0,58 por cento) determinando uma incidência significativamente alta da patologia, da ordem de 1 para cada 172 nascimentos. Além dessa incidência, relatam ainda o relacionamento dessa entidade com fatores conhecidamente implicados na sua gênese, tais como o sexo e a apresentaçao fetal.