Adaptive Immunity Flashcards - ch 13

Flashcards for reviewing adaptive immunity concepts.

Characteristic of Adaptive Immune Response

Specificity

Distinguishes between ‘self’ & ‘non-self’.

Memory

Humoral Immunity

Branch of adaptive immunity involving B cells and antibodies and BCR

Cellular Immunity

Branch of adaptive immunity involving T cells, TCR, helper T cells, cytotoxic T cells

B cells

Cells involved in Humoral Immunity.

T cells

Cells involved in Cellular Immunity.

BCR

B cell receptor.

TCR

T cell receptor.

Helper T cells (TH)

T cells that coordinate/direct immune responses.

Cytotoxic T cells (CTL)

T cells that kill host cells infected with intracellular pathogens.

Antigen (Ag)

Protein or polysaccharide recognized by the immune system.

Epitopes

Subset of a particular Ag, where an Ab or TCR actually bind on the Ag.

Antibodies (Abs)

Proteins, immunoglobulins (Ig) that bind to Ag and are major effector molecules of humoral immunity.

IgG

Antibody class involved in complement activation, neutralization, opsonization, etc.; crosses placenta, monomer

IgM

Antibody class that can act as BCR; pentamer acts in complement activation, neutralization, agglutination, pentameter

IgE

Antibody class that triggers release of antiparasitic molecules from eosinophils and of histamines from basophils and mast cells (allergic reactions), monomer

Neutralization (Ab Binding Effect)

Antibodies block the site(s) on pathogens, preventing adherence.

Inactivates virus, bacteria, neutralize/inactivate toxins

Opsonization

Enhancement of phagocytosis by coating with Ab, which enhances ingestion and lysis of bacterium by phagocytic cell

Oxidation

Antibodies possess catalytic property where they produce hydrogen peroxide which allows to kill bacteria directly

Agglutination

Antibodies cause antigens to clump together which makes it easier for phagocyte to ingest

Antibody-dependent cellular cytotoxicity (ADCC)

Antibodies attached to target cell cause destruction by macrophages, eosinophils, and NK cells.

Die through apoptosis not phagocytosis

NK cells dont learn pathogen specifically, only recognize Abs bound to microbes

Major Histocompatibility Complex (MHC)

Receptors found on all cells except RBCs involved in recognition of self and rejection of foreign tissue; also known as human leukocyte antigen (HLA).

MHC class 1 (intracellular Ag)

found and exist on ALL nucleated cells and present foreign antigens to all special cells called CTLs

involved in getting rid of infected cells/viruses/microbes that are infecting host cell

associated with marker called CD8

required for T lymphocytes

recognized by CTL (CD8+T cells)

MHC class 2 (extracellular Ag)

receptors that recognize and react with foreign Ag; located primarily on macrophages and B cells

involved in presenting Ag to T cells

associated with marker called CD4

recognized by TH cells (CD4)

B-cell receptors

Bind free antigens.

APC (antigen presenting cell)

Cells that process and present antigens to T cells, initiating an adaptive immune response.

types: activated macrophage, dendritic cells, B cells

once they eat something, they are activated and go to nearest secondary lymphoid tissue to display Ag to T cells

activated through binding of TLRs or by cytokines

T-cell receptors

Bind processed antigens.

Helper T cells

coordinate/direct immune response

identified by CD4 glycoproteins on surface of cells

cytotoxic T cells

kill host cells infected with intracellular pathogens

identified by CD8 glycoproteins on surface of cells

cellular immunity - T cell education

requires direct interaction with APC

takes place in secondary lymphoid organ

must be educated and learn Ag present on pathogen before they can attack

APCs display Ags to T cells on MHC molecules on outside surface of APC

T-dependent antigen

Most proteins; B cells need Ag to also be recognized by T cells for full activation.

T-independent antigen

Large polysaccharides; have repeating structures/subunits; B cells do not need T cell help to become fully activated.

Antibody titer

Level of antibodies in the serum.

Antigen Presenting Cells (APC)

Cells that display Ags to T cells on MHC molecules; 2 main types: dendritic cells & macrophages.

Perforin

Enzyme that makes pores in the cell membrane; CTL released molecules that induces apoptosis in target cell

Granzyme

Proteases that induce apoptosis; CTL released molecules that induces apoptosis in target cell

Apoptosis

Programmed cell death, changes occur in the cell membrane to signal phagocytes to ingest them.

Cytokines

Soluble molecules released mainly by leukocytes to communicate and coordinate/direct the immune response.

protein signals