Intro Flashcards
What are the two types of immunity?
Innate and Adaptive
What makes up primary lymphoid tissue?
Bone marrow and thymus
What makes up secondary lymphoid tissue where response takes place?
Lymph nodes, spleen, diffuse lymphoid tissues (tonsils)
What does humoral immunity consist of?
Circulating Abs from programmed cells that will label and/or kill abnormal invaders
What does cellular immunity consist of?
Programmed cells directly killing abnormal cells, or producing growth factors (cytokines) to stimulate other cells
What do B lymphocytes do and what percentage of blood lymphocytes do they make up?
1) Mediate the humoral response by making antibodies
2) Clonal expansion if stimulated by interleukins from helper T cells
3) differentiate into plasma cells that secrete Abs
10-20%
What two Abs act as receptors on B cells and activate them?
IgM and IgD
What are antibodies?
Glycoproteins that interact with epitope of an antigen
What is the general structure of an antibody? Be able to draw it (see notes).
Y-shaped with heavy and light chains that are connected with disulfide bonds and non-covalent forces
What region of the antibody has the Ag binding site? How many of these sites are there per Ab?
Fab region - 2
What region of Ab is constant and determines the Ab class?
Fc region
Which Ab is a pentamer that activates complement?
IgM
Which Ab activates B cells?
IgM
Which Ab is the initial Ab that is expressed during a response?
IgM
Which Ab is most common in blood and is a monomer?
IgG
Which Ab activates macrophages and neutrophils as well as complement cascades?
IgG
What is complement?
Plasma proteins, proenzymes, create protease cascade- when activated, opsonize pathogens and make the pathogen able to be recognized by phagocytes or for direct lysis
What Ab passes from mother to fetus through placenta or breast milk?
IgG
Which Ab is a dimer or trimer that is secreted in fluids and transported across epithelial layers?
IgA
Which Ab agglutinates antigen and activates effector cells?
IgA
Which Ab is bound to protein J?
IgA
Which monomer Ab binds to mast cells and basophils at its Fc region?
IgE
Which Ab stimulates release of histamine, heparin, and cytokines to increase vessel permeability so more cells can get to site faster?
IgE
Which Ab is active in allergies and destruction of parasitic worms?
IgE
Which Ab is present in extremely small quantities and is not very well understood?
IgD
What do T lymphocytes do and what % of blood cells are they?
Mediate cellular immunity through their T cell receptors when they are stimulated by MHC complex antigens.
What do cytotoxic T lymphocytes do? What molecular marker do they have? What MHC complex do they recognize?
Induce programmed cell death or lysis and undergo clonal expansion
They are CD8+ and recognize MHC-I Ag presenters
What do helper T lymphocytes do? What molecular marker do they have and what MHC complex do they recognize?
Secrete cytokines to stimulate other immune cells and undergo clonal expansion.
They are CD4+ and recognize MHC-II Ag presenters
What do regulatory T cells do? What molecular markers do they have?
Permit tolerance to self-antigens and are capable of suppressing the immune response
They are CD4+ and CD25+
What do Natural Killer cells do? What percentage of lymphocytes in blood do they make up?
Kill viral infected cells and tumor cells in a nonspecific/innate manner (no MHC class presentation) - release perforins to lyse cells or induce apoptosis
10-15%
What do macrophages do?
Phagocytose material coated with IgG, IgM, and complement
What do neutrophils do?
Phagocytose bacteria coated with IgG and IgM
What do mast cells and basophils do?
Release histamine, heparin, and chemotactic agents when activated with specific Ag
What do all nucleated cells present peptides with that allows them to be sampled by cytotoxic T cells?
MHC I
How do macrophages and B lymphocytes present antigens?
Present to helper T cells via MHC-II
Dendritic cells/Langerhans cells - in skin - can stimulate naive T cells
Follicular dendritic cells - in lymph nodes
What are Langerhans cells? Where do they present Ag?
APCs/dendritic cells in skin that can stimulate naive T cells. Present in lymph nodes.
What are follicular dendritic cells? Where do they exist?
Different class that does not process Ag - only binds
Present in lymph nodes
