Lecture 6: Adaptive Immune Responses

adaptive

specific “trained” immune response that changes over time in response to an agent (antigen), any substance that incites an immune response, especially antibody production

antigen

any substance, such as a virus, bacteria, pollen, or a cancer cells

what is immune surveillance

cells are stationed in or must move through body tissues to seek our target antigens, come back into blood stream via lymphatics

what are cell mediated (T lymphocytes/T cells)

respond to antigenic stimulation to nucleus kill cells or activate other immune cells

what is a humoral response

activated B lymphocytes called plasma cells begin producing antibodies which circulate in blood or cross body surfaces

what is lymphoplasmacytic inflammation

not much to see unless lymphocytes and plasma cells build up

what does lymphocytic mean

T or not yet active B cells

what does lymphoplasmacytic mean

LC and activated B cells (plasma cells)

what are the adaptive immune response types

tolerance, cytotoxic, and helper

what is the tolerance response

regulatory and lymphocytes (Treg) dampen responses to routine/commensal agents that maintain health

what is the cytotoxic response

cytotoxic T lymphocytes (Tc) target and remove internally infected or “foreign” cells (viral inf., neoplasia)

what is the helper response

helper T lymphocytes (Th) help activate other cells such as B cells

self-tolerance

• lymphocytes circulate in blood and lymph

• constantly recycled

• recognize self vs non-self via major histocompatability complex (MHC) molecules on cell surfaces

• helps immune cells recognize invaders as non-self (“foreign”)

what is clonal deletion

• while maturing, cells that recognize self antigens are removed by apoptosis thru “clonal deletion”

• occurs in thymus

antibody (Ab) aka immunoglobulin (Ig)

• proteins secreted by plasma cells that target antigen-molecule or particle that triggues immune response

• may be attached to cell surface, circulate in blood, or be secreated across membranes

• specific binding sites in arms of Y target

• flag cells for destruction by sticking to target antigen on surface receptors

• or coat over agents/organisms to enhance phagocytosis by macrophages — opsonization

importance of reassortment

• adapt to any potential target, even unknown threats, lymphocytes must produce an almost infinite # of unique sequences for antibody or T cell receptor to match ANY potential antigen

what is reassortment

rearrangement of sequences in cell development and mutated during clonal expansion lead to more specific binding to target antigen

what are memory T cells

after an adaptive response, some T cells are retained indefinitely to “remember” and rapidly

what are adverse effects of antibody/antigen binding

• anemia (body attacks own blood cells)

• amyloidosis

• renal deposition of antibody-antigen complexes

• skin blistering (ulcers)

• demyelination of nerves

immune-mediated hemolytic anemia (IMHA)

• antibodies begin attaching to body’s own blood cells

• blood cells coated by antibody are targeted for early destruction

amyloid

extracellular accumulation of waste protein, including excess antibody production

what is renal deposition

antibody-antigen complexes can get trapped in the filtration system of kidney (glomerulus) preventing normal renal function

what is skin blistering

• antibodies attack cell attachments in skin or cell to basement membrane attachments below skin

• forms fluid filled blisters that rupture and crust over

what is demyelination

• T cells begin recognizing self antigents from CNS

• attacking neurons and activate macrophages to remove myelin shealth wrapping around neurons → slowed nerve conduction