quiz 1 final review

• The third line of defense is adaptive (acquired) immunity.
• Dendritic cells act as the messenger between the innate and adaptive immune responses.
• B cells represent a smaller portion of blood lymphocytes.
• Complement can opsonize and cause lysis.
• Humoral adaptive response includes antibodies, cytokines.
• T lymphocytes are involved in the cell mediated immune response.
• B cells are distinguished by the CD5 CD marker.
• B cells can be transformed into memory B cells and plasma cells.
• CD4 marker on helper T cells helps T cell bind with antigen presented by macrophage or other APC.
• Mature T lymphocytes reside in lymph nodes and spleen.
• Antigens are substances that stimulate antibody formation or sensitize T-cells and can bind to an antibody.
• Foreign substances are only antigenic if their membranes or molecular components can be recognized as foreign.
• Antigens are bound to the ends of the heavy chain (1/4) and the light chains (1/2) contain regions of amino acids that differ from one antibody molecule to another.
• The constant region of the antibody is responsible for binding to host tissue and complement activation.
• The Fab consists of one light chain and one half of the heavy chain.
• Papain can split the antibody into three parts: two Fab and one Fc.
• IgA2 is a dimer and is found in secretions such as tears, saliva, colostrum, milk, intestinal fluids.
• IgG is the monomer; it has four subclasses and accounts for 70-75% of Ig in blood.
• Pepsin splits antibody at the heavy chain just below the disulfide bridge.
• fixes complement; main antibody of primary response; B cell receptor; immune system memory - IgM
• IgA is a monomer and is found in serum.
• Opsonins are molecules that will bind to a cell surface and promote phagocytosis by cells that bear receptors.
• Complement leads to red cell breakdown or lysis.
• After antigen binding, the Ig molecule promotes phagocytosis because macrophages and other cells have receptor on their surface that binds the Fc region of the molecule. This process is called opsonization
• IgA1 is a monomer and is found in serum
• MW of antigens that rarely cause a response is <5000 daltons
• MW of better antigens >10000 D
• antigens are rarely lipids
• antigens are also called immunogens
• an epitope is the part of hte antigen that reacts specifically with the antibody or T cell receptor
• O gene - amorph or silent gene (no gene product)
• As a general rule, 85% of Caucasians are Rh positive
• The h gene - don't produce L-fucosyltransferase
• Lectin - a plant extract that binds to specific RBC antigens
• Para Bombay

  • patients have no H gene and therefore can't make H antigen on their red cells (and no A or B antigens)
  • this lacks of an H gene means they can't make the enzyme FUT1 (fucotransferase 1) which is necessary to make H substance on their RBC
  • no H substance, but some "floats on" from other sources
• Para Bombay

  • Secretions/Plasma
  • Have a gene (Se) that allows them to make FUT2 (fucotransferase 2), so have H substance in their secretions and plasma, but not on their red cells
  • if they have A or B genes, sometimes they make A and B antigens in their plasma that float onto their red cells, and we see weak reactions with anti-A and anti-B (Ah or Bh)
• Anti-B, Anti-AB, and Anti-H

  • It is believed that anti-A,B reacts with an epitope (antigen site) that both A and B antigens have in common