Antibodies in Infection Flashcards
What are the effector lymphocytes and the regulator lymphocytes?
Effectors: B lymphocytes, CD8 T lymphocytes, K cells and NK cells
Regulators: CD4 T lymphocytes, cytokines and regulatory T cells
What are the three ways that recognition is achieved?
Recognition of common characteristics
Recognition of unique characteristics of foreign substances
Recognition of something common in an uncommon context
How is recognition different between T lymphocytes and B lymphocytes?
B cells can recognise loads of things
T cells can only recognise short peptide antigens
Describe antibodies
Immunoglobulins made up of four polypeptide chains (2 heavy 2 light) held together by disulphide bonds. 8 constant regions and 4 variable regions
What are the two varieties of antibody responses?
Primary response (lag of a few days before antibodies specific to new antigen appear in blood) Secondary response (larger and faster antibody response)
Where do antibodies come from?
Antigens bind to receptors on B cells, which is then activated by a helper T cell. The B cell then proliferates and differentiates into memory B cells and plasma cells. Plasma cells produce antibodies
Why does splenomegaly occur in infection?
Lots of immature immune cells travel to secondary lymphoid organs (such as the spleen) to mature and fight the infection
What are the four ways that antibodies work in the body?
Direct neutralisation (Antibodies coat virus and render it unable to bind)
Opsonisation (antibodies increase the affinity of phagocytes to the virus increasing phagocytosis efficiency)
Antibody-Dependent Cell-Mediated Cytotoxicity (K cells bind to a virus via C3b or an antibody delivering short range cytotoxicity)
Complement activation
What is complement activation?
20 proteins in the blood that act as an enzyme cascade
Two pathways: Classical- antigen antibody complexes
Alternative- pathogen surfaces
Results in chemotaxis (C3a), opsonisation (C3b) and lysis (C3b)
