What is the differences of vine and johnsy?

In O. Henry's short story "The Last Leaf," the characters of Johnsy and Sue (often referred to as "Vine") are distinct in their personalities and outlooks on life. Johnsy is portrayed as a pessimistic and fragile young woman who loses her will to live when she becomes ill, while Sue is more optimistic and determined, embodying a nurturing spirit. Their contrasting attitudes highlight the themes of hope and despair, with Sue's supportive nature ultimately inspiring Johnsy to fight for her life. Johnsy's transformation reflects the impact of love and friendship in overcoming adversity.