That's the latest shade from Emmanuel Sanders to AB ... and yeah, their beef clearly ain't dead yet.

ICYMI -- Sanders and the Steelers superstar have gone back-and-forth over the last month ... all stemming from Brown's issues in Pittsburgh.

Sanders ripped AB's season-ending antics on an appearance on NFL Network in mid-January ... saying Brown's actions were disrespectful to his teammates AND to Steelers ownership.

Brown fired back on Twitter ... Sanders responded -- and the full-blown beef was on.

The barbs had quieted down over the last couple weeks -- so, we had to ask Sanders when we got him out at the Super Bowl if the rift with AB was dead.

"Who's Antonio Brown?" the Broncos WR replied.