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Questions and Answers
What is the primary role of memory B cells in the immune system?
What is the primary role of memory B cells in the immune system?
Which statement is accurate regarding the surface characteristics of B-cells?
Which statement is accurate regarding the surface characteristics of B-cells?
How many antibodies can a plasma cell secrete per second?
How many antibodies can a plasma cell secrete per second?
Which of the following correctly describes MHC molecules?
Which of the following correctly describes MHC molecules?
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What is one function of antibodies in the immune system?
What is one function of antibodies in the immune system?
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Which of the following is NOT a type of innate immune cell?
Which of the following is NOT a type of innate immune cell?
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What is one key feature of the innate immune response?
What is one key feature of the innate immune response?
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Which cells are primarily involved in the process of phagocytosis?
Which cells are primarily involved in the process of phagocytosis?
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Which immune cells play a vital role in immunological surveillance?
Which immune cells play a vital role in immunological surveillance?
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What are the four classical signs of inflammation?
What are the four classical signs of inflammation?
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Which of the following is considered a physical barrier in immune defense?
Which of the following is considered a physical barrier in immune defense?
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Which of the following substances is part of the innate immune system's natural antimicrobial agents?
Which of the following substances is part of the innate immune system's natural antimicrobial agents?
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What characteristic defines the speed of the innate immune response?
What characteristic defines the speed of the innate immune response?
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What is the primary role of T cytotoxic (TC) lymphocytes?
What is the primary role of T cytotoxic (TC) lymphocytes?
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What membrane glycoprotein do T cytotoxic lymphocytes express?
What membrane glycoprotein do T cytotoxic lymphocytes express?
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When are T cytotoxic lymphocytes activated?
When are T cytotoxic lymphocytes activated?
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How do CD8+ T-cytotoxic cells induce cell death?
How do CD8+ T-cytotoxic cells induce cell death?
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What is the function of interferon-gamma (IFN-γ) secreted by CD8+ T cells?
What is the function of interferon-gamma (IFN-γ) secreted by CD8+ T cells?
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What is the role of T helper (TH) lymphocytes?
What is the role of T helper (TH) lymphocytes?
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What type of MHC molecules do TH lymphocytes recognize?
What type of MHC molecules do TH lymphocytes recognize?
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What co-receptor is expressed by B cells?
What co-receptor is expressed by B cells?
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What is the consequence of random generation of B cell receptors?
What is the consequence of random generation of B cell receptors?
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What is the production rate of antibodies by plasma cells?
What is the production rate of antibodies by plasma cells?
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What indicates a recent infection when testing blood antibodies?
What indicates a recent infection when testing blood antibodies?
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What process tests B cells for reaction to self proteins before they mature?
What process tests B cells for reaction to self proteins before they mature?
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What type of antibodies do B lymphocytes primarily produce during the initial response?
What type of antibodies do B lymphocytes primarily produce during the initial response?
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What happens to B cells that strongly react to self proteins?
What happens to B cells that strongly react to self proteins?
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What is the primary function of T lymphocytes in the immune system?
What is the primary function of T lymphocytes in the immune system?
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Which of the following describes the ability of antigen-specific immunity after initial exposure?
Which of the following describes the ability of antigen-specific immunity after initial exposure?
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What is the normal range of lymphocytes in the blood per liter?
What is the normal range of lymphocytes in the blood per liter?
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What type of immunity do B lymphocytes primarily mediate?
What type of immunity do B lymphocytes primarily mediate?
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Which surface proteins are responsible for presenting bits of the cell's contents to the immune system?
Which surface proteins are responsible for presenting bits of the cell's contents to the immune system?
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What is the life span of lymphocytes?
What is the life span of lymphocytes?
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What percentage of lymphocytes in the blood are T lymphocytes?
What percentage of lymphocytes in the blood are T lymphocytes?
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Which type of lymphocyte is known for producing antigen-specific antibodies?
Which type of lymphocyte is known for producing antigen-specific antibodies?
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What does 'CD' signify in the context of lymphocytes?
What does 'CD' signify in the context of lymphocytes?
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What occurs in the thymus during the maturation of thymocytes?
What occurs in the thymus during the maturation of thymocytes?
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Which type of immunity do Natural Killer (NK) cells belong to?
Which type of immunity do Natural Killer (NK) cells belong to?
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What is the primary role of the thymus in the immune system?
What is the primary role of the thymus in the immune system?
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What molecules do CD8+ T cytotoxic cells recognize?
What molecules do CD8+ T cytotoxic cells recognize?
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What characterizes Large Granular Lymphocytes (LGL)?
What characterizes Large Granular Lymphocytes (LGL)?
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Which statement accurately describes memory B cells?
Which statement accurately describes memory B cells?
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What is the function of plasma cells in the humoral immune response?
What is the function of plasma cells in the humoral immune response?
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Which of the following is true regarding the CD markers on T-helper and T-cytotoxic cells?
Which of the following is true regarding the CD markers on T-helper and T-cytotoxic cells?
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Which of the following distinguishes MHC-I from MHC-II molecules?
Which of the following distinguishes MHC-I from MHC-II molecules?
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What is the primary role of antibodies in the immune response?
What is the primary role of antibodies in the immune response?
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What is the primary function of Major Histocompatibility Complex (MHC) molecules in the immune system?
What is the primary function of Major Histocompatibility Complex (MHC) molecules in the immune system?
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Which statement about T lymphocytes is NOT true?
Which statement about T lymphocytes is NOT true?
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How many main HLA groups are inherited as a set in humans?
How many main HLA groups are inherited as a set in humans?
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Which of the following innate immune cells is specifically involved in phagocytosis?
Which of the following innate immune cells is specifically involved in phagocytosis?
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What is the role of thymocytes in the thymus?
What is the role of thymocytes in the thymus?
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What distinguishes the populations of lymphocytes?
What distinguishes the populations of lymphocytes?
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What feature differentiates the innate immune response from the adaptive immune response?
What feature differentiates the innate immune response from the adaptive immune response?
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Which statement accurately describes the role of Natural Killer (NK) cells?
Which statement accurately describes the role of Natural Killer (NK) cells?
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What is the main cellular difference between B lymphocytes and T lymphocytes?
What is the main cellular difference between B lymphocytes and T lymphocytes?
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What percentage of thymocytes die by apoptosis before reaching maturity?
What percentage of thymocytes die by apoptosis before reaching maturity?
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Identify the physical barriers that contribute to the innate immune defense.
Identify the physical barriers that contribute to the innate immune defense.
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What are the classical signs of inflammation that indicate a response to injury or infection?
What are the classical signs of inflammation that indicate a response to injury or infection?
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Which type of T cells are primarily responsible for recognizing and acting on MHC-I molecules?
Which type of T cells are primarily responsible for recognizing and acting on MHC-I molecules?
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Which natural antimicrobial substance is NOT part of the innate immune system?
Which natural antimicrobial substance is NOT part of the innate immune system?
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What characterizes the immune response associated with antigen-specific immunity after an initial exposure?
What characterizes the immune response associated with antigen-specific immunity after an initial exposure?
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Which cells can be classified as antigen-presenting cells (APCs)?
Which cells can be classified as antigen-presenting cells (APCs)?
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Which characteristic of the innate immune response contributes to its non-specific nature?
Which characteristic of the innate immune response contributes to its non-specific nature?
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In which part of the thymus do thymocytes undergo negative selection?
In which part of the thymus do thymocytes undergo negative selection?
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What type of immunity relies primarily on the recognition of specific antigens?
What type of immunity relies primarily on the recognition of specific antigens?
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What is the primary differentiating feature of Natural Killer (NK) cells?
What is the primary differentiating feature of Natural Killer (NK) cells?
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What does 'TH' denote in the lymphocyte classification system?
What does 'TH' denote in the lymphocyte classification system?
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What type of material do HLA molecules present to cell surfaces?
What type of material do HLA molecules present to cell surfaces?
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Which cell type executes the process of positive selection in the thymus?
Which cell type executes the process of positive selection in the thymus?
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What is the primary mechanism by which CD8+ T-cytotoxic cells induce cell death in infected or altered host cells?
What is the primary mechanism by which CD8+ T-cytotoxic cells induce cell death in infected or altered host cells?
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What is the consequence when a B lymphocyte binds to an antigen without proper co-stimulation?
What is the consequence when a B lymphocyte binds to an antigen without proper co-stimulation?
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Which of the following best describes the role of CD4+ T-helper cells in the immune response?
Which of the following best describes the role of CD4+ T-helper cells in the immune response?
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What characterizes the antibody production sequence in response to an infection?
What characterizes the antibody production sequence in response to an infection?
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What selective process ensures that B cell progenitors do not react strongly to self-proteins?
What selective process ensures that B cell progenitors do not react strongly to self-proteins?
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What is the primary function of the perforin protein secreted by CD8+ T-cytotoxic cells?
What is the primary function of the perforin protein secreted by CD8+ T-cytotoxic cells?
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Which surface marker do T helper lymphocytes utilize for their interaction with MHC molecules?
Which surface marker do T helper lymphocytes utilize for their interaction with MHC molecules?
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What distinguishes the most recent exposure in the context of antibody testing?
What distinguishes the most recent exposure in the context of antibody testing?
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How do B lymphocytes primarily recognize specific antigens?
How do B lymphocytes primarily recognize specific antigens?
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What mechanism do B cells undergo to eliminate those that strongly react to self proteins?
What mechanism do B cells undergo to eliminate those that strongly react to self proteins?
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What co-receptor provides assistance to T cells during activation through interaction with MHC molecules?
What co-receptor provides assistance to T cells during activation through interaction with MHC molecules?
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What describes the function of IFN-γ in the immune response?
What describes the function of IFN-γ in the immune response?
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What negative outcome might occur if B cells fail during central tolerance?
What negative outcome might occur if B cells fail during central tolerance?
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Match the following signs of inflammation with their Latin terms:
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Study Notes
Innate Immune Cells
- Include macrophages, granulocytes, neutrophils, eosinophils, basophils, mast cells, dendritic cells, and natural killer (NK) cells.
- Main features: fast, non-specific, and generic immune response.
- Innate immune cells involved in phagocytosis: macrophages, neutrophils, and eosinophils.
Adaptive Immune Cells
- Composed of highly specialized cells like B lymphocytes and T lymphocytes.
- B lymphocytes are responsible for humoral immunity through antibody production.
- T lymphocytes carry out cell-mediated immunity, targeting infected cells.
Phagocytosis and Immunological Defense
- Process by which macrophages, neutrophils, and eosinophils engulf and digest pathogens.
- Natural killer cells perform immunological surveillance, detecting virus-infected cells.
- Physical barriers include skin, epithelial membranes, hair, and one-way urine flow.
Antimicrobial Substances
- Natural substances that provide defense include HCl, lysozyme, natural antibodies, saliva, interferons, and complement proteins.
Inflammation
- Characterized by rubor (redness), calor (heat), dolor (pain), and tumor (swelling).
Antigen-Specific Immunity
- Unique to specific antigens and involves a time lag to maximum response.
- Offers immunological memory for faster responses upon re-exposure.
Lymphocyte Characteristics
- Normal range: 1.5-3.5 x 10^9/L in blood; can persist for many years.
- Central role in protecting against infections; slightly smaller than neutrophils.
- Large and round nuclei characteristic of lymphocytes; heterogeneous based on lineage and CD molecules expression.
Major Histocompatibility Complex (MHC)
- Cell surface proteins that present intracellular material to differentiate self from non-self.
- Found in all vertebrates; in humans, encoded by Human Leukocyte Antigen (HLA) genes.
- MHC-I is present on all nucleated cells; MHC-II is on antigen-presenting cells (APCs).
T Lymphocytes Development
- Produced and mature in the thymus, where they undergo positive and negative selection.
- CD4+ T helper cells and CD8+ cytotoxic T cells recognize MHC-II and MHC-I, respectively.
Functions of T Helper and Cytotoxic Cells
- TH lymphocytes aid in activating other immune cells by recognizing MHC-II.
- TC lymphocytes eliminate infected cells by recognizing MHC-I and inducing apoptosis.
B Lymphocytes Development and Function
- Produced and mature in the bone marrow, circulating in blood, spleen, and lymph nodes.
- Recognize antigens via surface antibodies (B cell receptors) and secrete antigen-specific antibodies.
Plasma Cells and Antibody Production
- Plasma cells can secrete up to 2000 antibodies per cell per second for a limited time.
- Initial antibody production is IgM, followed by IgG after class switching.
Memory B Cells
- Confer immunological memory for rapid responses upon subsequent infections.
- Found in the spleen and lymph nodes, express high levels of IgA, IgG, and/or IgE after class switching.
Mechanisms of Antibody Action
- Opsonization enhances phagocytosis; antibodies coat antigens for better recognition.
- Complement activation leads to the lysis of pathogens, augmenting immune response.
- Neutralization prevents toxins and pathogens from exerting harmful effects.
Summary of True/False Statements
- B-cells express CD19 on their surface: true.
- Plasma cells secrete 200 antibodies per cell per second: false (2000).
- Antibodies defend through complement activation, opsonization, and neutralization: true.
Types of Immunity
- Cell-mediated immunity involves T-cells, targeting intracellular pathogens and tumors.
- Humoral immunity, primarily through plasma cells, protects against extracellular threats.
Innate Immune Cells
- Innate immune cells include macrophages, granulocytes, neutrophils, eosinophils, basophils, mast cells, dendritic cells, and natural killer (NK) cells.
- The innate immune response is characterized by being fast, non-specific, and generic.
- Phagocytosis is performed by macrophages, neutrophils (acting as antigen-presenting cells), and eosinophils.
- Immunological surveillance at body surfaces is primarily conducted by NK cells.
Physical Barriers and Natural Antimicrobials
- Physical barriers such as skin, epithelial membranes, hairs, and one-way urine flow play vital roles in defense.
- Natural antimicrobial substances include HCl, lysozyme, natural antibodies, saliva, interferons, and complement proteins.
Inflammation
- Four classical signs of inflammation are rubor (redness), calor (heat), dolor (pain), and tumor (swelling).
Adaptive Immune Cells
- Adaptive immunity involves specialized cells and is unique to specific antigens.
- B lymphocytes are responsible for humoral immunity, producing antigen-specific antibodies.
- T lymphocytes are involved in cell-mediated immunity, targeting infected cells.
Lymphocyte Characteristics
- Lymphocytes range from 1.5 to 3.5 x 10^9/L in blood and can persist for many years.
- They are classified into T cells and B cells, with T lymphocytes accounting for 75% of lymphocytes in the blood.
- Lymphocytes have a large, round nucleus and are slightly smaller than neutrophils.
Major Histocompatibility Complex (MHC)
- MHC molecules present intracellular material to facilitate identification of self vs. non-self.
- MHC-I is found on all nucleated cells, while MHC-II is found on antigen-presenting cells (APCs).
- The human equivalent of MHC is Human Leukocyte Antigen (HLA), which consists of HLA-A, HLA-B, and HLA-DR groups.
- HLA group alleles include 59 for HLA-A, 118 for HLA-B, and 124 for HLA-DR.
T Lymphocyte Activation and Function
- CD8+ T cells, or cytotoxic T lymphocytes, recognize MHC-I and eliminate infected cells via apoptosis.
- CD4+ T cells, or T helper lymphocytes, recognize MHC-II and assist other immune cells through cytokine release.
- Thymocytes undergo positive and negative selection during their maturation in the thymus; 95-98% die before reaching maturity.
B Lymphocyte Production and Function
- B lymphocytes are produced and mature in bone marrow and circulate in blood, spleen, and lymph nodes.
- They recognize antigens via surface antibodies (B cell receptors) and produce antigen-specific antibodies once activated.
- Plasma cells, derived from B cells, secrete up to 2000 antibodies per cell per second and have extensive rough endoplasmic reticulum for secretory function.
Antibody Functions
- Antibodies act through opsonization, complement activation, and neutralization of toxins.
- IgM is the initial antibody produced, followed by IgG after class switching; the presence of both indicates recent infection, while only IgG indicates a longer period since infection.
Memory B Cells
- Memory B cells confer immunological memory, ensuring rapid response during re-exposure to pathogens.
- They primarily reside in the spleen and can produce high levels of antibodies such as IgA, IgG, and IgE after class switch.
Summary of True/False Statements
- B-cells have CD19 on their surface - true.
- Plasma cells can secrete 200 antibodies per cell per second - false, it’s 2000.
- Antibodies defend through complement activation, opsonization, and neutralization - true.
Immune Responses Overview
- Cell-mediated response involves T-cells, targeting intracellular pathogens and cancers through specific MHC interactions.
- Humoral response involves plasma cells secreting antibodies to combat extracellular bacteria and foreign macromolecules.
Innate Immune Cells
- Primary innate immune cells include macrophages, granulocytes (neutrophils, eosinophils, basophils), mast cells, dendritic cells, and natural killer (NK) cells.
- Macrophages and neutrophils are involved in phagocytosis, a process where cells engulf and digest pathogens.
- Natural Killer cells conduct immunological surveillance, identifying and attacking infected or abnormal cells.
- Physical barriers to infection include skin, epithelial membranes, hairs, and mechanisms like one-way urine flow.
- Natural antimicrobial substances: HCl, lysozyme, natural antibodies, saliva, interferons, and complement proteins are critical defensive elements.
Adaptive Immune Cells
- Adaptive immunity relies on highly specialized immune cells, particularly B lymphocytes (produce antibodies) and T lymphocytes (cell-mediated responses).
- B lymphocytes are associated with humoral immunity while T lymphocytes focus on cell-mediated immunity.
- T-helper cells (CD4+) assist other immune cells, while cytotoxic T cells (CD8+) eliminate infected cells.
Characteristics of Innate Immune Response
- Features include being fast, non-specific, and generic in nature.
- Inflammation displays four classical signs: rubor (redness), calor (heat), dolor (pain), and tumor (swelling).
Lymphocyte Features
- Lymphocytes, slightly smaller than neutrophils, have a large, round nucleus occupying most of the cytoplasm.
- Normal range of lymphocytes in blood: 1.5-3.5 x 10^9/L, with a lifespan that can extend for many years.
- Lymphocytes are classified into two main types: T cells and B cells, crucial for immune response.
Role of Major Histocompatibility Complex (MHC)
- MHC molecules enable the immune system to distinguish self from non-self by presenting intracellular material at the cell surface.
- Found in all vertebrates, MHC genes in humans are referred to as Human Leukocyte Antigen (HLA), including HLA-A, HLA-B, and HLA-DR groups.
- MHC-I is present on all nucleated cells, while MHC-II is found on antigen-presenting cells.
T Cell Maturation and Function
- T cells mature in the thymus through a process of positive and negative selection, ensuring functional and self-tolerant T cell populations.
- CD8+ T cytotoxic cells target MHC-I complexes, while CD4+ T helper cells recognize MHC-II complexes.
- Cytotoxic T cells induce apoptosis in infected cells using perforin to create pores.
B Lymphocyte Overview
- B lymphocytes produce and mature in the bone marrow, circulating through blood, spleen, and lymph nodes.
- Their primary role is production of antigen-specific antibodies, which neutralize toxins and pathogens.
- Memory B cells, formed post-activation, ensure rapid responses upon re-exposure to pathogens.
Antibody Functions
- Antibodies perform key actions: opsonization enhances phagocytosis, complement activation leads to lysis of pathogens, and neutralization prevents pathogen action.
- Plasma cells secrete high volumes of antibodies (up to 2000 per second), primarily IgM initially, followed by IgG after class switching.
Summary of Immune Responses
- Cell-mediated responses protect against intracellular pathogens; humoral responses target extracellular bacteria and foreign particles.
- Both types of responses involve complex interactions between various immune cells, receptors, and signaling molecules, ensuring effective immune defense.
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Description
Explore the fascinating world of innate and adaptive immune cells in this quiz. Test your knowledge on various immune cell types, their functions in phagocytosis, and the body's defense mechanisms. Dive into the specifics of B and T lymphocytes and discover how they contribute to immunity.