Reflection : Object reference not set to an instance of an object

I try to call a method using reflection. My object :

public class CurrentSearch
{
    public string currentUniverse { get; set; }
    public string currentApplication;
    public string currentUsage;
...

My code :

CurrentSearch cS = SessionUtils.getCS();
cS.currentUniverse = "lol";         
string methodName = "currentUniverse" ;
var test = typeof(CurrentSearch).GetMethod(methodName).Invoke(cS, null);

But i get the error "Object reference not set to an instance of an object." on the last line. I've checked cS, it's not null... What's wrong? Thx