6.2.4 Humoral Immunity

• Humoral immunity defends against pathogens using antibodies produced by B lymphocytes
• Antibodies secreted by plasma cells bind to antigens, neutralizing the pathogen
• Humoral immunity targets pathogens in bodily fluids like blood and lymph.
• Some activated B cells become memory cells, providing long-term immunity
• The key cells involved in humoral immunity are B lymphocytes and plasma
• B lymphocytes differentiate into plasma cells after recognizing antigens.
• APCs present antigens bound to MHC Class II molecules to T helper cells
• Steps in antigen presentation and B cell activation:

  1️⃣ Antigen uptake by APCs

  2️⃣ Antigen presentation on MHC II

  3️⃣ T helper cell activation

  4️⃣ B cell activation

  5️⃣ Differentiation into plasma cells and memory cells
• In cell-mediated immunity, T lymphocytes and macrophages directly kill infected cells
• What are the key players in humoral immunity?

  B lymphocytes, antibodies
• Humoral immunity targets extracellular pathogens
• Humoral immunity neutralizes pathogens through antibody binding.
• Steps in the humoral immunity process

  1️⃣ Antigen recognition

  2️⃣ B cell activation

  3️⃣ Antibody production

  4️⃣ Formation of memory cells
• What type of pathogens does humoral immunity defend against?

  Extracellular pathogens
• Match the type of immunity with its key players:

  Humoral Immunity ↔️ B lymphocytes, antibodies

  Cell-Mediated Immunity ↔️ T lymphocytes, macrophages
• Which cells are involved in humoral immunity?

  B lymphocytes, plasma cells
• B lymphocytes differentiate into plasma cells.
• Plasma cells secrete antibodies to neutralize pathogens
• What is the role of B lymphocytes in humoral immunity?

  Recognize antigens, differentiate into plasma cells
• What is the role of plasma cells in humoral immunity?

  Produce and secrete antibodies
• Steps in the process of antigen presentation and B cell activation

  1️⃣ Antigen uptake by APCs

  2️⃣ Antigen presentation on MHC II

  3️⃣ T helper cell activation

  4️⃣ B cell activation
• Which cells act as antigen-presenting cells (APCs) in humoral immunity?

  Macrophages, dendritic cells
• Antigens are presented on APCs bound to MHC Class II
• What do T helper cells recognize on APCs during antigen presentation?

  MHC II-antigen complex
• Which molecules secreted by activated T helper cells stimulate B cells?

  Cytokines
• B cells require binding to the same antigen via their BCRs for full 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
• Events in the process of antigen presentation and B cell activation

  1️⃣ Antigen Uptake by APCs

  2️⃣ Antigen Presentation

  3️⃣ T Helper Cell Activation

  4️⃣ B Cell Activation
• Antigen-Presenting Cells (APCs) engulf pathogens or antigens and break them down into peptide fragments
• What do MHC II molecules display?

  Antigens
• B cells require binding the same antigen via their B cell receptors for full activation.
• What type of cells engulf pathogens in antigen uptake?

  APCs
• Plasma cells produce and secrete large amounts of antibodies
• Match the cell type with its role in humoral immunity:

  B lymphocytes ↔️ Recognize antigens

  Plasma cells ↔️ Produce antibodies
• Memory B cells provide long-term immunity by quickly responding to future exposures.
• What is the primary function of memory B cells?

  Long-term immunity
• What type of cells recognize antigens and initiate the immune response?

  B lymphocytes
• Plasma cells produce and secrete antibodies
• B lymphocytes recognize antigens as part of their role in humoral immunity
• What do B lymphocytes differentiate into during humoral immunity?

  Plasma cells