In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

[Q]:  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 .
[A]: HIV - 1


[Q]:  Positive and negative regulation of granulopoiesis by endogenous RARalpha .
[A]: endogenous RARalpha


[Q]:  Given these facts , over the last 10 years , several investigators have measured the number of glucocorticoid receptors in normal and neoplastic lymphoid tissue to see whether their number correlated with glucocorticoid responsiveness in vitro or in vivo .
[A]:
glucocorticoid receptors