Cryopreserved PBMCs are a common specimen source for studies of immunological responses to vaccines,
immunotherapies, etc. The health and viability of cells recovered post-cryopreservation are of course
critical to the success and accuracy of immunological assays performed on them. This protocol standardizes PBMC isolation and cryopreservation techniques, specifically for the
assessment of thawed cells by cytokine flow cytometry.