Humoral Immunity

Question 1

humoral immunity

Answer 1

defense against extracellular pathogens

mediated by B cells

Question 2

plasma cells

Answer 2

produce antibodies in lymph tissues/organs

antibodies perform function at sites distant from production

Question 3

effector function of antibodies?

Answer 3

neutralization, opsonization, and complement activation

Question 4

neutralization

Answer 4

antibody binds to pathogen so it can’t gain entry to cell

sterically hinders the pathogens

**only requires binding to antigen

Question 5

opsonization

Answer 5

microbe that is crosslinked with IgG

-phagocyte binds the Fc-gamma-RI receptors and activate it to ingest an kill pathogen

Question 6

ADCC

Answer 6

antigen-dependent cellular cytotoxicity

NK binds to antibody-coated cells by Fc receptor and destroy these cells

Question 7

mucosal immunity

Answer 7

IgA is secreted

**very important

Question 8

neonatal immunity

Answer 8

antibody transport across the placenta and ingested in breast milk

IgG FcRn - transports across placenta
IgA in breat milk

Question 9

what Abs for complement activation?

Answer 9

IgG and IgM

Question 10

why is IgG so much more protective than IgM

Answer 10

IgM can only activate complement
IgG can activate phagocytosis and complement
-IgG also activates NK cells

Question 11

CD19+ population?

Answer 11

B cells

Question 12

CD3+ populaiton?

Answer 12

pan T cell marker

Question 13

hyper IgM immunodeficiency

Answer 13

inability to class switch**
aka HIGM

five genetic types

prone to bacterial and opportunistic infections
neutropenia, failure to thrive, thrombocytopenia, and anemia are common

Question 14

X-linked HIGM?

Answer 14

defective CD40L expression

Question 15

why are there antibodies to blood group antigens but not to tetanus toxoid antigens?

Answer 15

blood antigens - sugars
-t independent only produce IgM

tetanus - proteins

Question 16

IVIG

Answer 16

pooled human immunoglobulins
-treatment for autoimmune/inflammatory diseases

though to engage inhibitory FcR on B cells (inflammatory)

also used to provide Igs (autoimmune)

Question 17

cryoglobulinemia

Answer 17

chronic infection can lead to immune complex disease

-requires persistent immune response

immune complexes may become immunogenic
-IgM made against IgG

mechanism unknown

presence of ICs in kidneys, small blood vessels, and other organs

Question 18

why would monoclonal antibody against CD20 help cryoglobulinemia patients

Answer 18

CD20 pan-B cell marker

would target B cells for death - no antibody problem