Functions of Cells and Molecules Involved in Immunity

B cell
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Terms in this set (11)
B cell
Lymphocyte that resides in the lymph nodes, spleen, or other lymphoid tissues, where it is induced to replicate by antigen-binding and helper T cells interactions; its progeny (clone members) form plasma cells and memory cells
Plasma cell
Antibody-producing "machine"; produces huge numbers of the same antibody (immunoglobin); represents further specialization of B cell clone descendants
Helper T cell
A T cell that binds with a specific antigen presented by a macrophage; it stimulates the production of other immune cells (cytotoxic T cells and B cells) to help fight the invader; acts both directly and indirectly by releasing cytokines
Cytotoxic T cell
Also called a killer T cell; activity enhanced by helper T cells; its specialty is killing virus-invaded body cells, as well as body cells that have become cancerous; involved in graft rejection
Regulatory T cell
Slows or stops the activity of B cell or T cells once the infection (or attack by foreign cells) has been conquered. Thought to be important in preventing autoimmune diseases
Memory cell
Descendant of an activated B cell or T cell; generated during the initial immune response (primary response); may exist in the body for years thereafter, enabling it to respond quickly and efficiently to subsequent infections or meetings with the same antigen
Antigen-presenting cell
Any of several cell types (macrophage, dendritic cell, B cell) that engulfs and digest antigens that it encounters and presents arts of them on its plasma membrane for recognition by T cells bearing receptors for the same antigen; this function, antigen presentation, is essential for normal cell-mediated responses. Also releases chemicals (cytokines) that activate T cells
Antibody (immunoglobulin)
Protein produced by a B cell or its plasma cell offspring and released into the body fluids (blood, lymph, saliva, mucus, etc) where it attaches to antigens, causing neutralization, precipitation, or agglutination, which "marks" the antigens for destruction by phagocytes or complement
Cytokines
Chemicals released by sensitized T cells, macrophages, and certain other cells:
Migration inhibiting factor-"inhibits" macrophage migration and keeps them in the local area
Interleukin 2-stimulates T cells and B cells to proliferate; activates NK cells
Helper factors-enhance antibody formation by plasma cells
Suppressor factors-suppress antibody of T cell-mediated immune responses (interleukin-10 transforming growth factor, and others)
Chemotactic factors-attract leukocytes (neutrophils,eosinophils, and basophils) into inflamed area
Gamma interferon-secreted by lymphocytes; helps make tissue cells resistant to viral infection; activates macrophages and NK cells; enhances maturation of cytotoxic T cells
Tumor necrosis factor (TNF) Complement
Like perforin, causes cell killing; attracts granulocytes; activates T cells and macrophages
Group of bloodborne proteins activated after binding to antibody-covered antigens; when activated, complement causes lysis of the microorganism and enhances inflammatory response
AntigenSubstance capable of provoking an immune response; typically a large complex molecule not normally present in the body