UNIT 2 (topic 4) specific immunity Flashcards
what is the difference between specific and non-specific immunity
non-specific = immediate response , same for all pathogens
specific = response is lower , specific for each pathogen
what type of cell is used in cell-mediated immunity
T- lymphocytes
where are T-lymphocytes produced and matured
produced in bone marrow and matured in the thymus
examples of antigen-presenting cell
phagocytes, body cells invaded by viruses, cancer cells, transplanted cells
what is the role of a helper-T-cell
- develops memory cells
- stimulates phagocytes
- stimulates B cells to divide
- stimulates cytotoxic T- cells
what is the role of the cytotoxic- T- cell
releases perforin which causes holes in the membrane - can’t control entry and exit of substances - can burst or shrivel
explain the steps of cell-mediated immunity
- phagocytosis occurs and the phagocyte is now an antigen- presenting cell
- helper T cells bind to complementary antigen and divide rapidly by mitosis
- cloned T cells split into the 4 roles
what type of cell is used in humoral immunity
B- cells
what is the main difference between T and B cells
- B cells attack invaders outside the cell
- T cells stimulate the responses
what is the role of a plasma cell
- secretes antibodies (made of proteins)
- leads to destruction of the pathogen
why is the plasma cell the primary response
antibodies only survive a short time
- immediate defence
what is the role of a memory cell
when encountered with the same antigen, divides quicker
develops into more memory cells or plasma cells
explain the stages of humoral immunity
- binds to complementary antigens and takes them up by endocytosis
- B cells then become antigen presenting cell - helper T cells activate B cells - CLONAL SELECTION
- B cells divide by mitosis - CLONAL EXPANSION and split into plasma or memory cells
