Reinfection cases by closely related SARS-CoV-2 lineages in Southern Brazil.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the pandemic that started in late 2019 and still affects people's lives all over the world. Lack of protective immunity after primary infection has been involved with reported reinfection cases by SARS-CoV-2. In this study, we described two cases of reinfection caused by non-VOC (Variants of Concern) strains in southern Brazil, being one patient a healthcare worker.

Optimal thawing of cryopreserved peripheral blood mononuclear cells for use in high-throughput human immune monitoring studies.

Cryopreserved peripheral blood mononuclear cells (PBMC) constitute an important component of immune monitoring studies as they allow for efficient batch- testing of samples as well as for the validation and extension of original studies in the future. In this study, we systematically test the permutations of PBMC thawing practices commonly employed in the field and identify conditions that are high and low risk for the viability of PBMC and their functionality in downstream ELISPOT assays. The study identifies the addition of ice-chilled washing media to thawed cells at the same temperature as being a high risk practice, as it yields significantly lower viability and functionality of recovered PBMC when compared to warming the cryovials to 37 °C and adding a warm washing medium.