How does Jo affect Dickens' story? Is he a sympathetic character?

Jo represents the neglected innocent people in our society. He is bounced around and used by people, is always in some kind of trouble and cannot be safe so long as he is forced to live in the street and fend for himself. Jo is kind and good, but his need to survive makes him easy prey for those more fortunate, as well as for the legal system. His illness and death portray him as the ultimate victim and Dickens reminds the reader that we are all to blame.