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Antigen‐specific CD8 T cells in cell cycle circulate in the blood after vaccination
Author(s) -
Simonetti Sonia,
Natalini Ambra,
Folgori Antonella,
Capone Stefania,
Nicosia Alfredo,
Santoni Angela,
Di Rosa Francesca
Publication year - 2019
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/sji.12735
Subject(s) - antigen , cytotoxic t cell , biology , immunology , flow cytometry , cd8 , vaccination , t cell , lymph , antigen presenting cell , virology , immune system , medicine , pathology , genetics , in vitro
Although clonal expansion is a hallmark of adaptive immunity, the location(s) where antigen‐responding T cells enter cell cycle and complete it have been poorly explored. This lack of knowledge stems partially from the limited experimental approaches available. By using Ki67 plus DNA staining and a novel strategy for flow cytometry analysis, we distinguished antigen‐specific CD8 T cells in G 0 , in G 1 and in S‐G 2 /M phases of cell cycle after intramuscular vaccination of BALB/c mice with antigen‐expressing viral vectors. Antigen‐specific cells in S‐G 2 /M were present at early times after vaccination in lymph nodes (LNs), spleen and, surprisingly, also in the blood, which is an unexpected site for cycling of normal non‐leukaemic cells. Most proliferating cells had high scatter profile and were undetected by current criteria of analysis, which under‐estimated up to 6 times antigen‐specific cell frequency in LNs. Our discovery of cycling antigen‐specific CD8 T cells in the blood opens promising translational perspectives.