The dog ate my homework Helper, the family dog, eating his homework. "I didn't know dogs actually did that", he says, and finds his teacher equally incredulous since he had used that excuse before. In a later episode, when the dog goes to work for the police, Bart must eat his own homework for the excuse to work. When Mrs. Krabappel begins dating Ned Flanders, the Simpsons' neighbor, at the end of the 2011 season, she sees Santa's Little Helper in the Simpsons' yard and asks if he is the dog who has eaten Bart's homework so many times. Bart's attempts to demonstrate this and
T helper cell because such knowledge may be very useful in the treatment of disease and in increasing the effectiveness of vaccination. Proliferating helper T cells that develop into effector T cells differentiate into two major subtypes of cells known as T1 and T2 cells (also known as Type 1 and Type 2 helper T cells, respectively). T1 helper cells lead to an increased cell-mediated response, typically against intracellular bacteria and protozoa. They are triggered by IL-12 and their effector cytokines are IFN-γ and IL-2. The main effector cells of T1 immunity are macrophages as well as CD8 T cells, IgG B cells,