Biotechnology Flashcards
Types of immunity and their functions
Innate immunity - first line of defense same defense for any pathogen, no memory component.
Adaptive immunity - special recognition with memory component
First hours, we dependent on innate immune responses.
Three lines of defense for the innate immune system
l. Skin & mucous membranes - epidermis with closely packed cells, mucous membranes which trap microbes and foreign substances
2. Cell intrinsic responses - interferons, produced by lymphocytes infected by viruses to prevent further spread
3. Call mediated defenses - phagocytes cells, natural killer cells.
How does the adaptive immune system work?
Adaptive responses are highly specific to the particular pathogen that induced them. Carried out by WBCs & work in tandem with innate immune responses. Two types of protective cells -) cytotoxic T cells directly attack antigens and bcells which transform into plasma cells making antibodies.
How do antigens train the immune system?
Any substance capable of eliciting a response from the immune system is an antigen. Tricks body into responding to foreign protein. This is called immunisation. This car induce an adaptive immune response that is specific to the macromolecule.
Difference between B&t cells in the immune system?
B lymphocytes are developed in the bone marrow whereas the T cells in thymus. After activation from antigens both develop into effector cells. Bcells transform into plasma cells, have endoplasemic reticulum around them which makes the antibodies. T cells generate a variety of signal proteins called cytokines, which act as loyal mediators.
How do bcells produce such a diversity of specific antibodies?
Clinal selection theory- animal randomly generates vast diversity of lymphocytes and then selects for activation those that can react with the particular antigen. As lymphocytes develop they are already committed to what antigen they’re gonna face. This is expressed through surface receptor proteins which only bind to the antigen. The binding of antigen to these receptors causes the lymphocyte to activate & proliferate, producing more cells with the same receptors- clonal expansion
Memory B cells vs naive B cells
Memory B cells produce antibodies of different classes and of much higher affinity for the antigen than naive B cells. Main reason why secondary > primaryresponse.
How can the immune system fight against itself?
Self tolerance system can break down cause T&b cells to reach against the organism’s own tissues. Immune reactions against insulin secreting cells is why people get diabetes.
Structure of an antibody
Abs are immunoglobulins. They are secreted by Bcells. 4 peptide chains 2 heavy (H) chains, 2 light (L) chains. Variable (V) region at tips of each H and L chain-usually contain 2 antigen-binding sites. Constant (C) region – remainder of H and L chain.
Roles for antibodies
Neutralise antigens.
Immobilise bacteria
precipitate antigens
Enhance phagocytosis
Activate complement
Which subclass of immunoglobulins does the B cell make first?
IGM
What is alternative splicing and hypervariable loops?
