CD137 molecule permits single cell sorting and expansion of HIV-specific T cells in vitro
Objective 
To isolate HIV-specific T cell clone and to expand them in vitro through the activation-induced expression of CD137 molecule. 
 
 
Methods 
The peripheral blood mononuclear cells were isolated from HIV-infected patients and HIV Gag specific CD3+ CD8+ CD137+ T cell subset were sorted to 96-well plate in 1 cell/well by multicolor flowcytometry and single cell sorting. After 14 days in vitro culture with feeder cells and cytokines, the numbers and phenotypes of the cultured HIV-specific T cells were calculated and identified. 
 
 
Results 
The CD137 expression was low on rested T cells but up regulated by the stimulation with Gag peptide pool. The CD8+ CD137+ T cells could secret IFN-γ. The number of CD8 T cells reached to 106 after 14 days in culture and expanded to 107-108 cells after 28 days of culture in vitro 100% of the cells remained activated upon Gag stimulation. 
 
 
Conclusion 
In stead of using IFN-γ, CD137 could be utilized as a novel molecule to isolate and expand HIV specific T cells in vitro. The expanded antigen specific T cell clones could maintain good activation status. 
 
 
Key words: 
CD137; HIV; Single cell sorting; In vitro expansion