Chapter 15- Adaptive Immunity

adaptive immunity

antigen

any molecule that reacts specifically with an antibody, B cell receptor, or T cell receptor. It does not necessarily imply that it creates an immune reaction

humoral immunity

works to remove extracellular antigens

function of either B cells or B lymphocytes

B-cell/B-lymphocyte

plasma cell

fully differentiated B cell that produces antibodies

antibody

Y shaped proteins created by plasma cells that bind specifically to antigens, thereby targeting them for destruction & removal

cytotoxic T-cell (Tc)

helper T-cell (Th)

dendritic cell

antigen presenting cell that activates T cells

antigen-presenting cells

cells that collect and process antigen and present it on their surface to lymphocytes

memory lymphocytes/B-memory cells

cells that hold memory, are long lived, and respond much quicker upon re-exposure

primary response

first response to a particular antigen. It takes time, but leaves behind a memory of what was effective against that particular antigen

secondary response

subsequent, stronger, highy specific immune response

Peyer’s patches

lymph node structures on the intestinal lining where most infections occur

M cells

transfer samples of intestinal contents to lymphocytes that reside in Peyer’s patches

immunogen

an antigen that creates an immune reaction

antigenic

description of an antigen to elicit in immune response (ex- LPS is very antigenic)

epitopes

discrete region of an antigen molecule to which an antibody attaches itself (also called antigenic determinant)

clonal selection

major histocompatibility complex (MHC)

-molecules (class I and II) that present proteins (antigens) in their groove.

-way we identify “self”

-vital for organ transplant patients

affinity maturation

process that produces minor changes in the various activated B cells that make the antibodies work better

class switching

switching the form or class of the antibody in response to cytokines produced by T helper cells

lymphatic system

collection of tissues and organs that bring the population of B cells and T cells into contact with antigens

what are the primary lymphatic organs?

bone marrow and thymus

what are the secondary lymphatic organs?

lymph nodes, spleen, tonsils, adenoids, peyer’s patch, and the appendix

primary response

first response to a particular antigen. takes time, but leaves behind a memory of what was effective against that pathogen

secondary response

subsequent, stronger, highly specific immune response

cell-mediated immunity

works to remove intracellular antigens

function of either T cells or T lymphocytes

which cells gather in the paracortex?

naive T cells

which cells gather in the follicle?

naive B cells

immunogen

antigen that creates an immune reaction

class switching

B cells change their antibody forms depending on cytokine signals from T helper cells. Ultimately improves the immune response

what MHC class do cytotoxic T cells use?

Class I

what MHC class do T helper cells use?

Class II

what CD marker do cytotoxic T cells and macrophages have?

CD8

what CD marker do T helper cells have?

CD4

what role do both MHC classes play in the immune system?

they present antigen from different sources to different lymphocytes (T cells and B cells)

Natural Killer (NK) cells

destroy tumor, virally infected, stressed, and possibly intracellularly infected (non-viral) “self” cells that lack MHC class I molecules on their surface

who double checks the antigen for T cells, and why?

macrophages, to avoid dangerous autoimmune reactions

who double checks the antigen for B cells, and why?

T helper cells, to avoid dangerous autoimmune reactions

where are B and T cells produced?

bone marrow

where do B cells mature?

bone marrow

where do T cells mature?

thymus

where do hematopoietic stem cells reside?

bone marrow

T/F- An immunogen is always an antigen but an antigen is not always an immunogen

TRUE- an antigen may or may not cause an immune response

Fc region

the constant region of an antibody; determines the class of the molecule

Fab region

variable region of the antibody; determines the antigen binding specificity

what cells activate B cells?

T helper cells

what antibody is initially made by B cells after activation?

IgM

IgE

associated with allergies

what is the second antibody class that is made?

IgG

IgM

involved in primary immune responses and activated compliment

IgA

a dimer that is primarily secreted into saliva and mucous

IgG

classic antibody, most abundant, and most long-lived

what are six important functions of antibodies?

1. opsonization

2. immoblization and prevention of adherence

3. activates compliment system

4. cross-linking

5. neutralization

6. antibody dependant cytotoxicity (ADCC)

what are the five antibody classes?

IgM, IgG, IgE, IgD, and IgA

what is presented in the groove of MHC class I molecules?

endogenous antigens

what is presented in the groove of MHC class II molecules?

exogenous antigens

what is one primary purpose of MHC?

it is one of the major ways the immune system recognizes something as “self”

steps of clonal selection

Development, Activation, Proliferation & Differentiation, Effector action

what cells activate T cells?

dendritic cells

what cells activate B cells?

T helper cells

know how T cells become activated by dendritic cells

1. dendritic cells collect antigen and travel to secondary lymphoid organs

2. dendritic cells present microbial peptides, which produces co-stimulatory molecules

3. naive T cells that recognize antigen and costimulatory molecules can become activated

4. Activated T cells proliferate and differentiate

what does anergic mean?

when dendritic cells collect harmless antigen and do not produce costimulatory molecules, T cells do not activate (anergic)

understand the basics of how a Tc cell recognizes an acts on a cell infected with a virus

1. Tc cell recognizes viral antigen presented on surface of infected cell using MHC class 1 molecules

2. Tc cell releases cytokines and inititates apoptosis of the infected cell

what is the job of a natural killer (NK) cell?

to destroy tumor, virally-infected, stressed, and possibly intracellularly infected “self” cells that lack MHC class 1 molecules on their surface

produce cellular apoptosis with the cytokine TNF (tumor necrosis factor)

In what cell can you visualize the rough ER using light microscopy?

plasma cell

what do plasma cells use the rough ER to do?

make thousands of antibodies per second

superactivator (“cheerleader”) Th cells

travel to sites of inflammation and can supercharge the abilities of macrophages, Tc, and neutrophils— making them faster and more aggressive

T-dependant antigens

most require Th confirmation for activation

superantigens

have multiple repeating epitopes where B cell receptors bind simultaneously, leading to B cell activation without the involvement of Th cells

can be polysaccharides (glycoproteins??)

ex- peanuts, latex, pollen

how many naive B cells exist?

210 billion

how many naive T cells exist?

100 billion