Interestingly, I would have said that pride is a characteristic that defines Darcy's character and prejudice that of the character of Elizabeth. However, if we think about it, both of these main characters display both pride and prejudice in their thoughts and actions towards each other. Darcy is clearly very prejudiced towards Elizabeth's family and in particular the fact that they come from a lower class than himself. He mentions in his letter that he sends to Elizabeth to explain his relationship with Wickham how her family connections are something that he could take no delight in when he was thinking about proposing to her. This is something that Lizzie, after some reflection, actually agrees with herself.
In the same way, Lizzie shows tremendous pride in the way that she rebuffs Darcy's proposal and in how she thinks of Darcy and treats him when she hears the story that Wickham tells her of how Darcy wronged him. Even though Jane advises moderation, Lizzie is so headstrong that she continues to believe what she chooses to believe even when evidence begins to point the finger at Wickham rather than Darcy.
Pride and prejudice are the two major failings of these characters, and this is particularly important in the story of Wickham and in Lizzie's social standing. These are two ways in which these qualities keep Darcy and Lizzie apart for so long. They have both to learn how to moderate their pride and prejudice in a healthy way to be worthy of each other and the happy ending that awaits them.