raise turn or call down?

[brettbrettr]

Second orbit, but I just took a big pot off of BB when I 3-bet his AJ UTG with my 55 from the CO (which may in and of itself been a bit laggy with an unknown).

Anyhoo, I've been seeing a good deal of this in my short time at 6 max, the BB c/r'ing the flop or turn on a ragged board assuming the raiser had u/i overs....Without a read, in this spot, what line do you guys take? I realize its very read dependant, but in this case if he called and bet I'd fold the river u/i (which I hate doing)....other option of course is to call and call a river bet and perhaps lose to some crap pair.

Party Poker 5/10 Hold'em (6 max, 4 handed) converter

Preflop: Hero is UTG with A[img]/images/graemlins/spade.gif[/img], J[img]/images/graemlins/heart.gif[/img].
<font color="#CC3333">Hero raises</font>, <font color="#666666">2 folds</font>, BB calls.

Flop: (4.40 SB) 4[img]/images/graemlins/diamond.gif[/img], 5[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets</font>, BB calls.

Turn: (3.20 BB) 5[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets</font>, <font color="#CC3333">BB raises</font>, <font color="#CC3333">Hero 3-bets</font>, BB folds.

Final Pot: 8.20 BB