Adaptive immunity and vaccination Flashcards
Gibe 4 adaptive immune responses:
antigenic specificity
diversity
immunological memory
self/non-self destruction
How does the grade of response differ in innate and adaptive immunity?
innate: invariant, the number of times we have encountered the organism doesn’t matter
adaptive: modulated by memory, where response is quicker the second time
How are lymphoid cells split?
into T (thymus gland) cells (helper and cytotoxic) and B (bone marrow) cells (plasma cells - produce antibodies)
What is the difference between T cells and B cells?
T cells: cell mediated immunity, responds to foreign material INSIDE body cells
B cells: humoural immunity, produces antibodies, responds to foreign material OUTSIDE body cells
What is the difference between T cells and B cells?
T cells: cell mediated immunity, responds to foreign material INSIDE body cells
B cells: humoural immunity, produces antibodies, responds to foreign material OUTSIDE body cells
Describe CD4 T helper cells:
recognise APCs on MHS class II (macrophages, not any cell)
2 categories:
a) Th 1 cells: stimulate cell mediated immunity
b) Th2 cells: stimulate growth of specific plasma cell and antibody secretion
Stimulates humoural immunity and secrete cytokines
Describe CD8 T cytotoxic cells:
recognise APCs on MHS class I triggers cytotoxicity (cell mediated immunity)
What are the three types of APCs?
- B cells
- Macrophages
- Dendritic cells
these 3 are the only cell type that express MHC class II proteins (all WBCs)
What is the role of B lymphocytes?
they function in humoural immunity of the adaptive immune system by secreting antibodies (e.g. IgG, IgE)
How do T cells ‘help’ B cells?
before the B cell can produce antibodies, the Th cell releases cytokines that signal the B cells to divide and secrete the antibodies
What is the structure of an immunoglobulin/antibody?
2 light chains with an antigen attaching site (N terminal) and 2 heavy chains which direct the antibody to the right cell in the immune system (C terminal)
What are the 4 functions of antibodies?
- opsonisation - coats antigen with proteins that can be detected
- neutralisation - of the toxin produced by the bacteria
- activation of complement proteins
- Antibody dependent cytotoxicity - destruction of antibody coated target cells by NK cells
Where are dendritic cells located?
in the structural component of the lymphoid organs such as the thymus, lymph nodes and spleen
What is the role of dendritic cells?
They capture the antigen or bring it to the lymphoid organs where an immune response is initiated by presenting the antigen to the T cells
What are the 2 types of specific acquired immunity?
- humoural (B cells) and cell mediated (T cells)
How do memory cells work?
they lay dormant in the lymphatic system for years, if they detect a pathogen with the specific antigen, they can clone rapidly and secrete antibodies
What do vaccines do?
upon infection, rapidly secrete antigen specific antibodies
Define vaccine immunogenicity:
ability of a vaccine to induce antibodies
Define vaccine efficacy:
reduction in the incidence of a disease around people who have received a vaccine compared to unvaccinated people
Define vaccine effectiveness:
Ability of a vaccine to protect the community and is revealed after a vaccine is introduced in a vaccination programme
What is the difference between active and passive immunity?
Active: acquired through natural infection/immunisation and is long lasting
Passive: conferred by maternal antibodies/immunoglobulin preparations and is short lasting
Which disease has a vaccine which is of killed virulent organisms?
whooping cough
Which disease has a vaccine which is of live, non-virulent strains?
Rubella
Which disease has a vaccine which is of modified toxins?
Diptheria
