Question

What are some of the effector functions of antibody? What is the purpose of the different classes of antibody (Examples: IgG, IgE, IgA, IgM)?

Answer 1

effector functions of antibody

• Antibody binds extracellular pathogens and toxins to mediate their destruction by phagocytosis.
• there are 4 important methods by which antibodies exert their effects

a)Neutralization- antibody binds the pathogen and prevents the infection.

b) Opsonization- antibody contains both a Fab region,which is specific for an antigen , and an Fc region ,or constant region. when toxins covered antibody , the Fc region of these antibody can be recognized by phagocytic cells during the process of opsonization.

c) Complement action- complement is a system of plasma proteins activated by antibodies bound on a cell.the complement system activate phagocytes to destroy bacteria.

d) Antibody -dependent cellular cytotoxicity-occurs when Fc protein bounds to the surface of a cell interacts with Fc receptoron immune cells such as macrophages , and neutrophills.

classes of antibody	purposes
IgG	It detoxifies harmful substances and important in recognition of antigen- antibody complexes by leukocytes and macrophages. it transferred from mother to baby through placenta and protect the baby
IgM	B cells produces IgM first in response to microbial infection.it has higher avidity for antigen because of pentameric or hexameric structure.by binding cell surface receptor and activate cell signaling pathways
IgA	IgA in breast milk protects gastrointestinal tracts of neonates from pathogens.
IgE	its main role to protects against parasites, is primarly involved in allergy.
IgD	It involves in the induction of antibody production in B cells