21) The binding of complement proteins to certain sugar or proteins on a foreign cell’s surface is called __________.

22) Chemical secreted by white blood cells and macrophages called __________ help to increase the body’s preset temperature to promote a fever.

23) Cells studded with protein molecules found on our own cells that do not trigger an immune response within us (but may within others) are called __________.

24) Troublesome small molecules or incomplete antigens that may mount an attack that is harmful rather than protective are called __________.

25) Most B cell clone members become __________ cells.

26) The major role of __________ cells is to engulf antigens and present pieces of them to the cells that will deal with those fragments. 

27) Active immunity to tetanus, whooping cough, and polio can be artificially acquired when we receive __________.

28) The five major immunoglobulin classes are __________.

29) The region of the antibody that varies from antibody to antibody is called the __________ region.

30) Large antigen-antibody complexes can become insoluble and settle out of solution, a reaction called __________.

31) Killer T cells, which kill virus-invaded body cells, are also called __________.

32) Antigens that produce abnormally vigorous immune responses whereby the immune system causes tissue damage as it fights off a perceived threat that would otherwise be harmless are called __________.

33) Systemic (bodywide) acute allergic response caused by allergens that directly enter the blood, as with certain bee stings or spider bites, is called __________.

34) AIDS cripples the immune system by interfering with the activity of cells called __________.

35) A tropical disease that results when parasitic worms clog the lymphatic vessels is called __________.