Adaptive immune response Flashcards
What are the two components of the adaptive response and what they target
Humoral response - targets extracellular threats
Cell mediated response - targets intracellular threats
B cells, T cells and T helper cells are involved in which of the two components of adaptive immmune
B cells for humroal
T cells for cell mediated
T helper for BOTH
What does it mean when it says 3rd line of defense is specific and adaptive
Specific means its the ability to recognidr and respond to specific antigens
Adapative means that cells undergo immunological memory
What does it mean by immunological memory
Cells remember antigens after primary exposure and release a quicker stronger response against the same pathogen upon second expo
What is a lymphocyte
amd the two types of lymphocytes
Its a type of leukocyte that is specialised for the adaptive immune response and has a specfic receptor for a specific antigen for activation.
B lymphocytes and T lymphocytes
What is the humoral immune response
It is an adaptive immune response in which extracellular pathogens and toxins are destroyed via the production and secretion of Antibodies
What are the 3 main steps of humoral
- Clonal selection
- Clonal expansion
- Differentiation
Describe Humoral immune response
- A naive B cell meets and binds to an specific antigen that is complementary to B cell receptor in the secondary tissues, the B lymphocyte is now sleected. B cells then undergo antigen presentation by engulfing the pathogen, presenting it to the Helper T cell.
- The selected T helper cell will recognise and bind to the selected B cell. Releasing cytokines causing the B cell to undergo clonal expansion and differentiation
- The B cells proliferate into Plama B cells which produce antibodies specific to the antigens and Memory B cells which remain in the lymphoid tissue for immunological memory.
What is immunological memory
B memory cells
-remain in the tissue long after intial infection hasbeen clearlerd so upon secondary exposure, they will stimulate a stronger faster response.
What are antibodies
Protiens that are specigic to an antigen and are produced by B plama cells during humoral immune resoponse to destroy pathogens.
What structure is a antibody
Quatenary
How many long heavy chains and short light chains
How are the chains held together in antibodies
amd what part of antibody is different for each antibdoy
2x heavy , 2x light
Disulphide bonds
Variable reigion
What is the list of ways antibdoies neutralise pathogens
Activation of complement protiens
Immobolisation
Agglutination
Neutralisation
Opsonisation
remember PIANO
Explain the steps of selecting T helper Cells
- An antigen presentinc cell display pathogenic antigens on their surface via MHC 11 markers when pahgocytosing the pathogen.
- The APC cll then moves through the lymphatic system in from the afferent vessel of the lymphnode where it searches and binds to a complementary T cell receptor on a naive T helper cell surface
- The T helper cell if complementary is then activated and selected. The selected T helper cell can then initate an adaptive immune reponse bia humoral or cell mediated pathway.
What is cytotoxic T cells
Elimnate any body cell that are infected by pathogens or have abnormal or missing self markers
What kinda cells are missing self markers
Cancerous cells
What is neutralisation
Antibodies will bind to an antigen on a pathogen responsible site that is used to attack cells.
What is agglutination
Antibodies can bind to multiple antigens at once, forming a antigen-antibdoy complexes, making it easier for phagocytosis by a pathogen.
What is immobilisation
Antibdoies will bind to a pahtogen to slow or limit its movements
What is opsonisation
Makes it easier for a phagocytes to recognise and engulf pathogens
What is the activation of complement protiens
in reference to antibodies
Antibodies attach to the surface of pathogens and facilitate the actions of complement protiens, allowing it to form Membrane attack complexes
What cells is CD4+ protiens and what CD8+ protiens
- Helper T cell
- Cytotoxic T cell/memory T cells
How would memory T cells mount a faster and stronger immune response upon re-exposure?
T memory cells would proliferate rapidly and diffentiate into T helper cells and cytotoxic T cells after stimulation by an APC cell with the same antigen.
Descibe the cell mediated response
4 marker big one
- APC cell engulfs pathogen and undergoes antigen presentation, where it then travels through the lymph system to the lymph node, where it binds a complementary naive T helper cell receptor ( selecting it). As well as an naive T cell with a complementary antigen receptor.
- The selected T helper cell then activates selected T cell by secreting cytokines, causing it to proliferate and differentiate.
- The T cell will differnitate into cytotoxic T cells and T memory cells, where cytotoxic T cells leave the lymph node to the site of infection and specifically recognise and bind to antigens that are complementary to its receptors on a virally infected cell MHC 1 marker. Killing it by inducing apoptosis via perforin and granzymes
- and T memory cells remain in the tissue providing immunological memory where in future exposures, it can rapidly recognise the same viral antigens and proliferate and differentiate into cytotoxic T cellsm resulting in a stronger and more rapid immune response.
What other thing does T helper cells do with the Cytokines
And what the purpose of it is
Selected T helper cells secrete cytokines to also active naive T cells with CD4+ protiens to proliferate and differeniate into T helper cells.
Purpose: In order to amplify the immune response, sustain it over time, and ensure that the immune system has enough specialized T helper cells to effectively combat the infection.
