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 helper lineages and subsets. CD4 T helper cells can be divided into at least four lineages, namely, Th1, Th2, Th17 and Treg. These cells express master transcription factors (shown inside the cells, pSTATs stands for phosphorylated active STATs) and secrete signature cytokines (shown on the top of the cells).