6.2.4 Humoral Immunity

• What is humoral immunity and its role in the immune response?

  Defends against pathogens using antibodies
• Upon antigen binding, B cells become activated and differentiate into plasma cells.
• Steps in the process of humoral immunity

  1️⃣ Recognition: B lymphocytes recognize antigens on pathogens

  2️⃣ Activation: B cells differentiate into plasma cells

  3️⃣ Antibody Production: Plasma cells secrete antibodies

  4️⃣ Memory Cells: Some B cells become memory cells
• Memory cells provide long-term immunity in humoral immunity.
• Match the type of immunity with its key players:

  Humoral Immunity ↔️ B lymphocytes, antibodies

  Cell-Mediated Immunity ↔️ T lymphocytes, macrophages
• What is the target of humoral immunity?

  Extracellular pathogens
• Humoral immunity neutralizes pathogens through antibody binding.
• Cell-mediated immunity directly kills infected cells.
• What are the key cells involved in humoral immunity?

  B lymphocytes, plasma cells
• B lymphocytes recognize antigens and differentiate into plasma cells.
• Plasma cells produce and secrete antibodies.
• Steps in the process of antigen presentation and B cell activation

  1️⃣ Antigen Uptake by APCs

  2️⃣ Antigen Presentation via MHC II

  3️⃣ T Helper Cell Activation

  4️⃣ B Cell Activation

  5️⃣ B Cell Differentiation
• Match the cell with its role in antigen presentation and B cell activation:

  APCs ↔️ Engulf and process antigens

  T Helper Cells ↔️ Interact with MHC II-antigen

  B Cells ↔️ Activate via BCR binding
• Humoral immunity targets extracellular pathogens in blood and lymph.
• The key players in humoral immunity are B lymphocytes and antibodies.
• What type of pathogens does humoral immunity target?

  Extracellular pathogens
• The key cells involved in humoral immunity are B lymphocytes and plasma
• B lymphocytes recognize antigens and differentiate into plasma cells.
• Plasma cells produce and secrete antibodies to neutralize pathogens
• T helper cells recognize MHC II-antigen complexes via their TCRs.
• Activated T helper cells secrete cytokines that stimulate B cells to differentiate into plasma cells and memory cells.
• Steps in the process of antigen presentation and B cell activation

  1️⃣ Antigen uptake by APCs

  2️⃣ Antigen presentation by MHC II

  3️⃣ T helper cell activation

  4️⃣ B cell activation
• Match the molecule with its role in antigen presentation and B cell activation:

  MHC II ↔️ Displays antigens on APCs to T helper cells

  TCRs ↔️ Recognize MHC II-antigen complexes on T helper cells

  BCRs ↔️ Bind antigens on B cells

  Cytokines ↔️ Stimulate B cell differentiation
• Antigen-Presenting Cells (APCs) like macrophages and dendritic cells engulf pathogens
• APCs present peptide fragments bound to MHC Class II molecules.
• T helper cells recognize the MHC II-antigen complex via their T cell receptors
• B cells need to bind the same antigen via their BCRs for full activation.
• What class of MHC molecules is involved in presenting antigens to T helper cells?

  MHC Class II
• T helper cells recognize the MHC II-antigen complex via their TCRs
• Activated T helper cells secrete cytokines that stimulate B cells to differentiate into plasma cells and memory cells.
• What is the role of MHC II molecules in antigen presentation?

  Displays antigens to Th cells
• Match the molecule with its role in humoral immunity:

  TCRs ↔️ Recognize MHC II-antigen complexes

  BCRs ↔️ Bind antigens on B cells

  Cytokines ↔️ Stimulate B cell differentiation
• B lymphocytes differentiate into plasma cells and memory B cells after activation by T helper cells
• Plasma cells produce and secrete large amounts of antibodies to neutralize pathogens.
• Where are plasma cells primarily located?

  Lymph nodes and bone marrow
• Match the cell type with its primary function:

  Plasma Cells ↔️ Produce antibodies

  Memory B Cells ↔️ Provide long-term immunity
• What are antibodies primarily composed of?

  Glycoproteins
• An antibody consists of two heavy chains and two light chains linked by disulfide bonds.
• The Fab region of an antibody is responsible for binding to specific antigens
• Match the antibody function with its description:

  Neutralization ↔️ Prevents antigens from infecting cells

  Opsonization ↔️ Marks antigens for phagocytosis

  Complement Activation ↔️ Triggers complement cascade