Immunoglobulines IgG-IgD

University:
The University Of Western Ontario
Course:
Pathology 3500B | Human Pathology
Academic year:

2023
Views:

339

Pages:

3
Author:

Kyuwon J.

Immunoglubulines ● Glycoproteins in plasma cells => response to antigens ● Main effectors in humoral immunity ○ Pathogen neutralizations , oppositions + complement activations ■ 2 heavy chains +2 light chains in disulfide bonds ■ Constant regions determines its class (variabilities in regions of binding antigens IgG ● Most common in serum ○ 70-80% ● Placenta crossings = passive immunity to fetus ○ Neutralization on toxins + virus ○ Opsonization ■ Enhancing of phagocytosis ○ Activates classical complemental pathways ● Elevation in chronic infection ● Fab regions ○ One Constant +One variable domain ■ Both are from each heavy and light chains ○ Antigen binding sites ○ Specificity on antigens ● FC regions ○ Constant domain + heavy chains ○ Effector functions ■ Binding Fc receptor on macrophages/neutrophils/NK cells ● Hinge regions ○ Flexibility between domain and heavy chain ○ Antibodies to pair antigens in variable distance ● IgG subclass ○ IgG1 and IgG3: strong activators, efficient in oppositional ○ IgG2 ■ ○ IgG4 ■ ■ ■ Response to polysaccharide based antigens Not activated complements In chronic antigen or exposure Blocks antibody ● Competes with IgE for antigen binding ● Without triggering inflammation will just block hypersensitivity reactions (allergens) ● Outcome similar to antihistamine but is different in mechanisms IgA ● Mostly in mucosal secretions ○ Respiratory ○ Urogenital tracts ○ Gastrointestinal ● In monomer forms in serum but once in secretion they are in dimer form(secretory IgA) ○ First line of defence in mucosal surfaces ○ Prevention in microbial invasions ○ Passive mucosal immunity =>breast milks IgM ● Primary antibody to be in primary immune response ● pentamer (10 antigen binding sites) ● ● ● ● Stronger activators Effective in agglutination = multiple binding sites Significant in early stage immunity Cause cold autoimmune anemia IgE ● Lowest concentration in serum ● Fc receptor on mast cell + basophils ○ Mediation in allergic hypersensitivity ■ Fever, asthma, anaphylaxis ■ Defense on parasitic infections (helmithis) ● Elevated atopic disease + parasitic infection IgD ● Minimal amount in serum ● Immature B cells in surface receptors ○ Used in B cell activation + regulations ○ Not much is really known about this Immunoglobulin