Overview Flashcards
What are the 2 types of adaptive immunity, and what types of microbes do these adaptive
immune responses combat?
The two types of adaptive immunity are cell-mediated immunity and humoral immunity.
Cell-mediated immunity, mediated by T cells, is essential for protection against intracellular
pathogens. Humoral or antibody-mediated immunity provides protection primarily against
extracellular pathogens.
What are the differences between innate and adaptive immune responses?
Innate takes action in minutes/hours while adaptive takes days
Innate is less specific while adaptive discriminates even minor differences in molecular structure in microbes
adaptive may have failures in non-self discrimination leading to autoimmune diseases while innate is perfect
What are the principal classes of lymphocytes, and how do they differ in function?
B lymphocytes express surface immunoglobulin, which functions as their antigen receptor, and mediate humoral immunity. Following activation, B lymphocytes differentiate into
antibody-secreting plasma cells.
T lymphocytes express the T cell antigen receptor and either CD4 or CD8, and mediate cell-mediated immune response.
After activation by peptide antigens displayed by cell surface MHC molecules, CD4+ T cells secrete cytokines and express membrane-bound activating ligands, which induce inflammation, enhance the functions of phagocytes, and promote B cell antibody responses.
CD8+ T cells produce
cytotoxic proteins that induce the death of infected cells.
What are the primary and secondary lymphoid organs and what are their major functions?
Primary lymphoid organs are bone marrow and thymus. Bone marrow is the site of
generation of most mature circulating blood cells and the site of early events in B cell
maturation. Thymus is the site of T cell maturation.
Secondary lymphoid organs are mainly lymph nodes and spleen. Lymph nodes are
encapsulated, vascularized secondary lymphoid organs with anatomic features that favour
the initiation of adaptive immune responses to antigens carried from tissues by lymphatics.
Spleen is a highly vascularized organ whose major functions are to remove aging and
damaged blood cells and particles (such as immune complex) from the circulation and to
initiate adaptive immune responses to blood-borne antigens.
Neutrophil function
undergo phagocytosis and activation of bactericidal mechanisms
Basophil and Eosinophil
Eosinophil: main action against parasites, killing of antibody coated parasites
Basophil: Promotion of allergic responses, augmentaion of anti parasitic immunity
NK cell
Killing of viral infected cells via ADCC (Antibody dependent cell mediated cytotoxicity)
