immunity Flashcards
(32 cards)
innate immunity
The body’s first line of defense; non-specific and immediate.
What do neutrophils do?
Engulf and destroy bacteria through phagocytosis.
What do macrophages do?
Phagocytose pathogens and present antigens to adaptive immune cells.
What do dendritic cells do?
Capture antigens and activate T cells by presenting antigens in lymph nodes.
What do natural killer (NK) cells do?
Kill virus-infected and tumor cells without prior exposure.
What do mast cells do?
Release histamine and mediate allergic and inflammatory responses.
What are Pattern Recognition Receptors (PRRs)?
Receptors on innate cells that recognize common pathogen features (like TLRs).
What is adaptive immunity?
Specific immune response that develops after exposure to an antigen.
What do B cells do?
Recognize antigens and differentiate into plasma cells to produce antibodies
What do plasma cells do?
Secrete large quantities of specific antibodies.
What do helper T cells (CD4+) do?
Activate B cells and cytotoxic T cells; coordinate immune response.
What do cytotoxic T cells (CD8+) do?
Kill infected or cancerous cells directly by inducing apoptosis
What do memory T and B cells do?
Provide faster and stronger responses upon future exposures to the same antigen.
What does IgG do?
main antibody in blood; provides long-term immunity and crosses the placenta.
What does IgA do?
Found in mucosal areas (saliva, tears, breast milk); protects surfaces.
What does IgM do?
First antibody made during infection; effective at agglutinating pathogens.
What does IgE do?
nvolved in allergic reactions and protection against parasites.
What does IgD do?
Found on immature B cells; helps initiate B cell activation.
How does the immune system detect pathogens?
Innate immune cells use PRRs to detect PAMPs; adaptive cells use specific receptors.
How does antigen presentation work?
Dendritic cells present pathogen antigens on MHC molecules to T cells.
How is the adaptive response activated?
T cells recognize antigens via TCRs; helper T cells activate B cells to make antibodies.
How do antibodies fight pathogens?
Neutralize toxins, opsonize pathogens for phagocytosis, activate complement.
What is humoral immunity?
Immune response that involves B cells and the production of antibodies in body fluids (blood, lymph).
What is cell-mediated (cellular) immunity?
Immune response that involves T cells directly attacking infected or abnormal cells.
