41.  Which of the following most accurately describes how foreign substances can activate complement?  
A.  Antibodies can bind to foreign antigens and activate complement through the classical pathway.
B.  Foreign substances can bind to spontaneously activated C3 and stabilize it.
C.  Foreign proteins bind to C1 and activate it.
D.  Foreign proteins are phagocytized by macrophages and directly activate complement.
E.  Antibodies can bind to foreign antigens and activate complement through the classical pathway and foreign substances can bind to spontaneously activated C3 and stabilize it.

42.  Which of the following is NOT a mechanism of complement action?  
A.  produces cytokines
B.  opsonization
C.  attracts other immune cells to the site of infection
D.  forms a MAC that leads to cell lysis

43.  A surface chemical that prevents microbial growth is  
A.  histamine.
B.  leukotriene.
C.  sebum.
D.  kinin.
E.  interferon.

44.  A protein that helps to protect the body against viral infections is  
A.  complement.
B.  interferon.
C.  lysozyme.
D.  histamine.
E.  kinin.

45.  Interferon  
A.  directly attacks viruses.
B.  protects cells that have been invaded by viruses.
C.  increases vascular permeability.
D.  is not produced by most cells.
E.  is a protein that interferes with virus production and infection.

46.  Interferon production is stimulated by  
A.  a viral infection.
B.  the complement cascade.
C.  antigen-presenting cells.
D.  degranulation of basophils.
E.  inflammation.

47.  The movement of leukocytes to the source of certain chemicals is called  
A.  chemotaxis.
B.  opsonization.
C.  chemoreception.
D.  phagocytosis.
E.  hemolysis.

48.  Lysozyme is  
A.  an enzyme found in body fluids that destroys certain bacteria.
B.  a type of antibody that attracts a phagocyte.
C.  a cytokine produced by T cells.
D.  an antigen.
E.  a bacteria.

49.  The two major types of phagocytic cells are  
A.  neutrophils and monocytes.
B.  neutrophils and macrophages.
C.  monocytes and macrophages.
D.  lymphocytes and monocytes.
E.  eosinophils and T cells.

50.  Which of the following statements concerning neutrophils and macrophages is false?  
A.  They both exhibit chemotaxis.
B.  They both move by amoeboid motion.
C.  Both are capable of phagocytosis.
D.  Both release histamine when activated.
E.  Both can squeeze between cells.