Verified Answers Graded A+
ABO blood groups - Ans -Genetically determined classes of human blood; based on
the presence or absence of carbohydrates A and B on the surface of red blood cells. The
ABO blood group phenotypes, also called blood types, are A, B, AB, and O.
acquired immunity - Ans -The kind of defense that is mediated by B lymphocytes (B
cells) and T lymphocytes (T cells). It exhibits specificity, memory, and self-nonself
recognition. Also called adaptive immunity.
active immunity - Ans -Long-lasting immunity conferred by the action of a person's B
cells and T cells and the resulting B and T memory cells specific for a pathogn. Active
immunity can develop as a result of natural infection or immunization.
AIDS (acquired immunodeficiency syndrome) - Ans -The name of the late stages of
HIV infection, defined by a specified reduction of T cells and the appearance of
characteristic secondary infections.
anaphylactic shock - Ans -An acute, whole-body, life-threatening, allergic response.
antibody - Ans -A protein secreted by plasma cells (differentiated B cells) that binds
to a particular antigen and marks it for elimination; also called immunoglobulin. All
antibody molecules have the same Y-shaped structure and in their monomer form consist
of two identical heavy chains and two identical light chains joined by disulfide bridges.
antigen - Ans -A macromolecule that elicits an immune response by lymphocytes.
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, antigen presentation - Ans -The process by which an MHC molecule binds to a
fragment of an intracellular protein antigen and carries it to the cell surface, where it is
displayed and can be recognized by a T cell.
antigen receptor - Ans -The general term for a surface protein, located on B cells and
T cells, that binds to antigens, initiating acquired immune responses. The antigen receptors
on B cells are called B cell receptors (or membrane immunoglobulins), and the antigen
receptors on T cells are called T cell receptors.
antigen-presenting cell - Ans -A cell that ingests bacteria and viruses and destroys
them, generating peptide fragments that are bound by class II MHC molecules and
subsequently displayed on the cell surface to helper T cells. Macrophages, dendritic cells,
and B cells are the primary antigen-presenting cells.
apoptosis - Ans -The changes that occur within a cell as it undergoes programmed
cell death, which is brought about by signals that trigger the activation of a cascade of
suicide proteins in the cell destined to die.
autoimmune disease - Ans -An immunological disorder in which the immune system
turns against self.
B cell receptor - Ans -The antigen receptor on B cells: a Y-shaped, membrane-bound
molecule consisting of two identical heavy chains and two identical light chains linked by
disulfide bridges and containing two antigen-binding sites; also called a membrane
immunoglobulin or membrane antibody.
B lymphocyte (B cell) - Ans -A type of lymphocyte that develops to maturity in the
bone marrow. After encountering antigen, B cells differentiate into antibody-secreting
plasma cells, the effector cells of humoral immunity.
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