Role of lymphocytes in the immune system: T cells Flashcards
What happens when T cells move into the thymus gland to matures?
They become activated (by the hormone thymosin found in the thymus gland)
When is the thymus gland most active? What happens to its size?
in the first few weeks before and after birth.
It remains relatively active (and enlarges) up to puberty, when it begins to shrink in size.
Do T cells produce antibodies?
no. Instead they act against most viruses and some bacteria
Define Helper T cells
They stimulate B cells and killer T cells
Define killer T cells
They destroy abnormal human body cells
Define suppressor T cells
They inhibit the immune response
Define memory T cells
They survive for years after the infection is eliminated and can stimulate the specific B cells and killer T cells if the same infection later enters the body
What do helper T cells do? (3)
They recognise antigens on the surface of other white blood cells, especially macrophages.
They stimulate the multiplication of those B cells that produce the antibody that is specific to the recognised antigen.
Helper T cells also stimulate killer T cells to reproduce
What are killer T cells stimulated by?
by chemicals that are produced by helper T cells
What do killer T cells attack?
examples are virus-infected cells or cancer cells
What do killer T cells release? What does this do?
They release a protein called perforin, which forms pores in the membrane of the abnormal cell.
Water and ions flow into the abnormal cell through these pores, which bursts the cell.
What are killer T cells called/said to be?
cytotoxic cells
How are suppressor T cells stimulated?
By specific antigens to grow.
Do suppressor T cells grow faster or slower than other T and B cells?
slwoer
When are suppressor T cells most active?
They usually become more active after the antigen (and pathogen) has been destroyed
