Lymphatic system Flashcards
What are the two types of responses by the lymphocytes
Effector responses e.g. B lymphocytes
Regulatory responses eg. cytokine production (CD4 T lymphocytes)
how do lymphocytes get into various tissues including lymph nodes?
squeeze through specialized area of capillaries called high endothelial venules then once their job is done they go bact to the lymph nodes
What happens in the primary response to an antigen?
In the primary response where the adaptive immunity has not encountered the antigen before so it take sa few days before the affectors produce specific antibodies or cytotoxic t lymphocytes to bind to antigens. This leads to their neutralization and or removals. the primary response decreases as antigens are removed.
What happens in the secondary response to antigen?
Secondary response the immune reacts faster and more vigorously.
Describe the structure of antibodies?
4 pp chains held together by disulphide bonds and non covalent interaction.
2 h and l chains covalently bonded and have globular domains and variables that are antigen binding and constant regions.
How do B cells work to generate antibody responses?
virgin B lymphocytes are activiated to create the primary antibody responses. In secondary lymphoid organs, antigens select and bind to antigen sensitive BL that have surface immunoglobulin (sIg) receptors with appropriate affinity. cooperating system (helper T cells) give B cells signals. The B cells proliferate and mature into plasma cells that secrete soluble antibodies of the same antigen binding specificity.
Memory B cells are also produced simultaneously which are long lived beyond the virgin antigen sensitive BL and can be restimulated.
How do antibodies work?
Direct neurtalization
complement activation
opsonisation
antibody dependent cell mediated cytotoxicity
How is the complement system activated?
antibodies and bacterial cell wall components.
How is the classical pathway fo the compliment system activated?
antigen-antibody complexes
How is the alternative pathway fo the compliment system activated?
bacterial cell wall components.
How is the compliment system activated?
Phagocytic cells posses cell surface receptors for the Fc region of antibody molecules and for the C3b activated complement component. The use of the receptors is to bind with high affinity to antibody-coated foreign material or material to which C3b has adhered following complement activation.
What is antibody dependent cell mediated cytotoxicity
Small pop of lymphocites in the blood which do have classical B or T L characteristics and are referred to as aK cells.
They have Fc receptrors and C3b receptors on their surface and through these are able to recognize and bind to antibody coated or C3b coated foreign antigenic material. K cells are not phagocytic but instead are able to kill cellular material to which they become bound through antibody or C3b by delievering short range cytotoxicity factors.
