Task: Named Entity Recognition
Input (English):  To investigate the role of costimulation of OX40 in human immunodeficiency virus type 1 ( HIV - 1 ) infection by its natural ligand , gp34 , the OX40 - transfected ACH - 2 cell line , ACH - 2 / OX40 , chronically infected with HIV - 1 , was cocultured with paraformaldehyde ( PFA ) - fixed gp34 - transfected mouse cell line , SV - T2 / gp34 .
Output (English): HIV - 1