You have no such protection if you won't be incriminated by the answers (e.g. they are asking you about someone else). You can of course be involuntarily called as a witness in proceedings where you're not being prosecuted.
Logically, it would follow that if you don't know what a question IS, you can 'plead the fifth' to it on the basis that it could be incriminating. But again, IANAL.
You shouldn't either. They are not your friend.