Santa's Little Helper dog's Christmas-inspired name to be a sign. However, the greyhound finishes last. As Homer and Bart leave the track, they watch the dog's owner abandon him for losing the race. Bart pleads with Homer to keep the dog as a pet and he agrees after it affectionately licks him on the cheek. When Bart and Homer return home, Santa's Little Helper is assumed by the rest of the family to be a Christmas present. In various episodes, Santa's Little Helper can be seen chewing on newspapers and other objects in the Simpsons' household, destroying furniture, and digging holes in the
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,