The term ZBA (Zero Balance Account) is sometimes used to describe a transit account. In reality, ZBAs are a completely different story and are usually used in an acquiring and merchant account context, where one party opens the account and another sweeps (clears) it daily.
Helper T cells are the major driving force and the main regulators of the immune defense. Their primary task is to activate B cells and killer T cells. However, the helper T cells themselves must be activated.
T-cells, also called thymus cells or thymocytes, are a type of white blood cell called lymphocytes. They help fight against disease and infection. T-cells cells play a vital role in cell-mediated immunity.