Introduction to Adaptive Immunity

B cells provide antibody-mediated immunity against antigens and pathogens in body fluids.

Memory cells allow the immune system to respond more effectively and quickly upon subsequent exposures to the same antigen.

Tolerance helps the immune system ignore normal self-antigens, preventing autoimmune reactions.

<p>T cell-mediated immunity targets abnormal cells and pathogens within living cells, while B cell-mediated immunity targets pathogens in body fluids.</p> Signup and view all the answers

<p>Antigen recognition involves T and B cells identifying specific antigens, leading to targeted immune responses.</p> Signup and view all the answers

<p>The two main classes are cytotoxic T cells, which kill infected or abnormal cells, and regulatory T cells, which help modulate the immune response.</p> Signup and view all the answers

<p>Versatility in the immune system allows for the production of various types of lymphocytes, each specific to different antigens.</p> Signup and view all the answers

<p>Lymphoid stem cells give rise to B cells in bone marrow and migrate to the thymus to become various types of T cells.</p> Signup and view all the answers

<p>Antibodies neutralize pathogens by masking the dangerous parts of bacterial exotoxins and viruses, preventing their interaction with host cells.</p> Signup and view all the answers

<p>The primary response is slower, taking about two weeks to peak and then declining, while the secondary response is faster and more extensive due to the presence of memory cells.</p> Signup and view all the answers

<p>Lymphocytes are activated when they bind to specific antigens, leading to B cell activation, proliferation, and differentiation into plasma cells that produce antibodies.</p> Signup and view all the answers

<p>Class I MHC proteins are found on all nucleated cells, while Class II MHC proteins are primarily located on antigen-presenting cells like B cells and macrophages.</p> Signup and view all the answers

<p>The four types are Helper T cells which aid in activating B cells and cytotoxic T cells, Cytotoxic T cells which kill infected cells, Regulatory T cells that moderate immune responses, and Memory T cells which provide long-term immunity.</p> Signup and view all the answers

<p>The variable segment forms antigen binding sites specific to each antigen.</p> Signup and view all the answers

<p>An antibody consists of 2 parallel pairs of polypeptide chains: one pair of heavy chains and one pair of light chains.</p> Signup and view all the answers

<p>The five classes of antibodies are IgG, IgA, IgM, IgE, and IgD.</p> Signup and view all the answers

<p>IgM is the first antibody secreted after antigen exposure and can agglutinate pathogens.</p> Signup and view all the answers

<p>IgG constitutes about 80% of all immunoglobulins and can cross the placenta to provide passive immunity to the fetus.</p> Signup and view all the answers

<p>Agglutination occurs when antibodies bind to multiple antigens, causing them to clump together and form immune complexes.</p> Signup and view all the answers

<p>The constant segment forms the stable base of the antibody molecule and determines the antibody's class.</p> Signup and view all the answers

<p>They divide to produce memory T cells and more active cytotoxic T cells.</p> Signup and view all the answers

<p>Antibodies neutralize pathogens by binding to their specific binding sites, preventing them from attaching to host cells.</p> Signup and view all the answers

<p>Opsonization is the process by which antibodies coat pathogens to enhance phagocyte efficiency in engulfing them.</p> Signup and view all the answers

<p>Memory T cells remain in reserve and can quickly differentiate into cytotoxic T cells and helper T cells upon subsequent exposure to an antigen.</p> Signup and view all the answers

<p>Exposure to an allergen stimulates IgE antibodies, causing them to bind to basophils and mast cells, which release histamine.</p> Signup and view all the answers

<p>They activate and divide to produce more helper T cells and memory T cells, stimulating the activity of B cells.</p> Signup and view all the answers

<p>Suppressor T cells inhibit the function of T cells and B cells to regulate the immune response.</p> Signup and view all the answers

<p>Lymphocytes are stimulated to take action after exposure to antigens, which are mostly protein-based substances.</p> Signup and view all the answers

<p>MHC proteins are glycoproteins that assist in lymphocyte activation by presenting antigens on cell surfaces.</p> Signup and view all the answers

<p>Class I MHC proteins are found on all nucleated body cells, while Class II MHC proteins are located on specialized antigen-presenting cells and lymphocytes.</p> Signup and view all the answers

<p>A phagocyte becomes an antigen-presenting cell when it engulfs and lyses pathogens, displaying their fragments on Class II MHC proteins.</p> Signup and view all the answers

<p>Haptens are partial antigens that gain antigenic properties only when bound to body proteins, triggering an immune response.</p> Signup and view all the answers

<p>Antigen presentation is the process by which MHC proteins carry antigens to the cell membrane to signal their presence to T cells.</p> Signup and view all the answers

<p>Phagocytic cells are immune cells that engulf and digest pathogens. Examples include free macrophages, fixed macrophages, and microglia.</p> Signup and view all the answers

<p>Class II MHC proteins appear on the cell membrane when the cell is processing antigens.</p> Signup and view all the answers

<p>Class I MHC proteins present abnormal peptides from viral or bacterial infections on the plasma membrane, signaling to immune cells that the cell is infected.</p> Signup and view all the answers

<p>The expression of abnormal peptides is triggered by the infection of a body cell by viral or bacterial pathogens.</p> Signup and view all the answers

<p>Abnormal peptides are incorporated into Class I MHC proteins as they are synthesized at the endoplasmic reticulum.</p> Signup and view all the answers

<p>After synthesis and peptide incorporation, Class I MHC proteins are transported via vesicles from the endoplasmic reticulum to the Golgi apparatus and then to the plasma membrane.</p> Signup and view all the answers

<p>Phagocytic APCs engulf extracellular pathogens and display antigenic fragments bound to Class II MHC proteins on their plasma membrane.</p> Signup and view all the answers

<p>Displaying antigenic fragments allows the immune system to recognize and respond to foreign antigens, facilitating an adaptive immune response.</p> Signup and view all the answers

<p>Antigenic fragments are bound to Class II MHC proteins after the phagocytic cells engulf and process extracellular pathogens.</p> Signup and view all the answers

<p>Class I MHC proteins primarily present intracellular antigens, while Class II MHC proteins present extracellular antigens from pathogens.</p> Signup and view all the answers