Immunoglobulins (Ig). ADAPTIVE IMMUNE SYSTEM. T-lymphocytes T-cytotoxic Cytoyoxic B-lymphocytes Plasma cells Antibodies Response takes 7 to 10 days. Adaptive Immune System. T and B Lymphocytes Highly specific for pathogen Response improves with repeated exposure Memory
Plasma cells Antibodies
Response takes 7 to 10 days
1. Activate both the classical and alternative complement cascades,
2. Transcytose across epithelial cell layers to provide a barrier to pathogens at mucosal surfaces,
3. Travel transplacentally to confer maternal humoral immunity to the fetus and neonate,
4. Induce phagocytosis by macrophages and granulocytes via the process of opsonization,
5. Foster antibody-dependent cellular cytotoxicity by lymphocytes and NK cells,
6. Encourage anti-parasite immune responses by eosinophils,
7. Promote degranulation by mast cells and basophils,
8. Bind and inactivate foreign antigenic entities directly.
1. The induction of activation and differentiation,
3. Apoptosis of B lymphocytes,
4. To act as a high-affinity receptor for the recognition,
5. Internalization, degradation, and
eventual presentation of specific antigens to T cells.
The high avidity of IgM for both antigen and complement is crucial in the context of its role as a front-line defense mechanism.
Another means by which IgG antibodies communicate with the effector arms of the immune system is via the Fcg receptors (FcgRs).
IgE is present in serum in the lowest concentration of all the immunoglobulins.
Multivalent antigen can then cross-link the bound IgE, indirectly cross-linking the FceRI molecules as well. Ultimately, this causes mast cells and basophils to release granules containing inflammation-mediating substances and chemoattractants for a variety of cell types.
This IgE type of response can be vital in the clearance of parasites, it has the unfortunate consequences of also causing allergy and anaphylaxis in predisposed individuals.
Transmembrane immunoglobulins are found in a complex with two other proteins, Iga and Igb. Iga and Igb are disulfide-linked but the exact stoichiometry is unknown, nor is it known which chain binds to the heavy chain. Iga varies in its glycosylation depending on which heavy chain it associates with.