11-12. Antibodies and antigen receptors

What is the central tenant of the humoral immune response?

antibody production

antibodies are the product of _____ lymphocyte lineage

B

what must occur to mediate endocytosis of an antigen?

adjacent b cell receptor are cross linked by an antigen

After an antigen is processed what cell is it presented to?

T cell

What are 4 essential functions of B cells after they are activated?

clonal expansion = increased survival and mitosis

increase expression of costimulatory molecules

increase expression of cytokine receptors

migration out of lymphoid follicles into T cell rich areas

what occurs in the recognition phase of the humoral immune response?

mature B cell encounters an antigen

what occurs during the activation phase of the humoral immune response?

B cell differentiates, ,proliferates, and undergoes clonal expansion

what 4 outcomes does clonal expansion of a B cell promote?

antibody secretion

isotype switching

affinity maturation

memory b cell

what is the first type of antibody to be secreted by a B cell?

IgM

immunoglobulins

glycoprotein molecules which are produced by plasma cells in response to an immunogen and which function as antibodies

Immunoglobulins bind to what?

specific antigenic determinants

what is the primary function of antibodies?

antigen binding to result in protection of the host

what does the valency of an antibody refer to?

number of antigenic determinants that an individual antibody molecule can bind to

T/F: the valency of all antibodies is at least two

true

T/F: antibody binding = direct neutralization of pathogen only

false, many biological effects also occur

what are the three effector functions of antibodies?

1. antibodies can bind to antigens/ toxins and neutralize particle which can then by phagocytosed by macrophages

2. antibodies can be opsonins and tag bacteria with Fc receptor for phagocytosis and lysis

3. antibodies activate classical complement cascader

what cells have receptors than bind immunoglobulins?

phagocytic cells

lymphocytes

platelets

mast cells

basophils

how is the overall effector function of an antibody determined?

directly related to structure of antibody

what are the parts of an antibody molecule

variable region and constant region

what is found at the variable region?

heavy and light chains

antigen binding site (Fab)

what is found at the constant region?

two heavy chains

which region determines the antibody's biological role (Fc)?

constant region

what is an idiotype?

It is contained in the variable region where each B cell clone produces antibodies with different antigen binding sites

What are antibody isotypes based on?

heavy chain constant regions

what does each specific isotype reflect?

function of antibody and maturation stage of B cell

slide 19

what occurs in the recognition phase of the humoral immune response?