It gets very complicated because our immune system is very complex. It is not as simple as forgetting antibodies. The strength and duration of the immune response varies depending on which pathway is used. The are multiple types of cells and antibodies in our immune system. I will forward you a few good links later, if you would like some more background.
Also, there are common reinfections of chickenpox. It is called shingles, which is caused by the same virus. The disease presents itself differently once a person gets chickenpox. A person can also get shingles without having chickenpox if they have had the chickenpox vaccine!