Patho: Adaptive Immunity

adaptive immunity

the ability to recognize and remember specific antigens and mount an attack on them

Effector T Cells (Tc

•—cytotoxic - CD-8+ •Eliminate the antigen via apoptosis—cancer cells and viruses •Secrete cytokines to stimulating macrophages to increase phagocytosis

Antibodies

•—recognize antigens •Receptors on immune cells •Secreted proteins •Formed from B cells

Primary lymphoid organs

(bone marrow and the thymus) •Provide the environment for immune cell production and maturation •Thymus Gland—produces mature, immunocompetent T-lymphocytes, but naïve

Secondary lymphoid organs

(lymph nodes, spleen, secretory) •Function to trap and process antigen and promote its interaction with mature immune cells

The nursing instructor is reviewing the plan of care with a nursing student who is caring for a client with an immune disorder, and they discuss the classes of human antibodies,. Which statement by the nursing student indicates a need for further teaching? 1. "Immunoglobulin G (IgG) is the minor serum antibody." 2. "Immunoglobulin M (IgM) is the first antibody produced in response to an antigen." 3. "Immunoglobulin E (IgE) accounts for less than 1% of the total antibody level in the blood." 4. "The major serum antibody is IgG, which constitutes about 70% of the total circulating antibodies."

1. "Immunoglobulin G (IgG) is the minor serum antibody." (Incorrect statement= need for further teaching)

The nurse has been assigned to care for a client with an immune disorder. In developing a plan of care for this client, the nurse incorporates knowledge that the immune system consists of specific major types of cells. Which types of cells are associated with the immune system? Select all that apply. 1. Dendritic cells 2. B lymphocytes 3. Red blood cells 4. Helper T lymphocytes 5. Cytolytic T lymphocytes

1. Dendritic cells 2. B lymphocytes 4. Helper T lymphocytes 5. Cytolytic T lymphocytes

Learning Outcomes

1.Compare and contrast the innate and adaptive immune response 2.Discuss the function and components of the adaptive immune system 3.Understand the differentiation of B and T cells 4.Compare and contrast humoral and cellular adaptive immunity 5.Identify the functions of the primary, secondary, systemic and secretory lymphoid organs 6.Identify the effects of aging on the immune system

The nursing student conducted a clinical conference on the role of B lymphocytes in the immune system. Which statement by a fellow nursing student indicates successful teaching? 1. "They activate T cells." 2. "They produce antibodies." 3. "They initiate phagocytosis." 4. "They attack and kill the target cell directly."

2. "They produce antibodies."

The nurse is administering immunizations as well as providing education to the client who receive them at a. health care clinic. Which statement by a client indicates that teaching was successful? 1. "Immunizations protect against all diseases." 2. "Immunizations can provide natural immunity." 3. "Immunizations can provide innate immunity." 4. "Immunizations are a way to acquire immunity to a specific disease."

4. "Immunizations are a way to acquire immunity to a specific disease."

Innate Immunity vs. Adaptive Immunity Responses

Innate: •Immediate •The same (non-specific) •Short-lived •No memory Adaptive: •Slow •Specific •Long-term •Memory

Helper T cells (Th)

•- CD4+ •Differentiates into T cells that produce cytokines or regulatory cells that control the immune response •Help to develop Tc and B cells, activate macrophages, form T-regulatory cells (Treg)

IgM antibodies

•1st immunoglobulin produced in a fetus, first produced during infection •IgM can switch to become IgG

Immune Response

•Active—direct exposure to the antigen, immunization •Passive—antibodies and T cells are transferred from a donor to a recipient vMother to fetus, in breast milk vImmunotherapy vImmunoglobulins laced with antigens

Regulatory Cells (Treg)

•Assist in orchestrating, controlling and limiting the immune response

Elderly Immune System

•Declining ability to adapt to environmental stresses •Decline in immune responsiveness •Decrease in the size of the thymus gland and decreased ability to participate in t-cell differentiation •Diminished T-cell function and response to antigen stimulation

Humoral Response

•Driven by antibodies produced by mature B Lymphocytes •B Lymphocytes •Formed in bone marrow •B lymphocytes create antibody-antigen complexes leading to neutralization or phagocytosis •Primary response—takes 1-2 weeks •Secondary response—memory phase, rise in antibodies occurs sooner and at a higher level

Development of an Immune Response

•Fetal development at 5 to 6 weeks •Secondary lymphoid organs well developed at birth •Maternal IgG protects a newborn for 6 months •IgA, IgM and newborn IgG develop shortly after birth •Reach adult levels by 1 year of age

Spleen

•Filters antigens from blood •Important in systemic infections

Lymph Nodes

•Found along axillae, groin, great vessels, neck, thorax, abdomen •Remove foreign material from lymph before it enters the blood stream •Proliferates and promotes activity of T-lymphocytes

Major Histocompatibility Complexes

•MHC 1 responds to endogenous cells that are injured or infected •MHC 2 responds to exogenous antigens

Accessory cells

•Macrophages and dendritic cells •Function as antigen-presenting cells (APCs) by the processing of a complex antigen into epitopes required for the activation of lymphocytes

Mucosal Associated Lymphoid Tissue (MALT)

•Plasma cells secrete antibodies in tears, sweat, mucus, breast milk •IgA is dominant secretory immunoglobulin •Prevents invasion and attachment of bacteria in the GI, GU, respiratory tracts

Summary

•There is a systemic immune system and a local immune system in the GI, GU and respiratory tract (MALT). There are primary lymphoid organs (bone marrow and thymus gland), and secondary lymphoid organs (lymph nodes, spleen) •Adaptive immunity is memory immunity. It differs from Innate immunity because it takes a longer time to respond, has memory that makes it recognize specific antigens, lasts a long time. •Humoral immunity is when B lymphocytes (B cells) develop into plasma cells that secrete antibodies. Antibodies bind to antigens that are presented by macrophages and dendritic cells, the APCs. B cells can also act as APCs to T cells. A plasma cell can produce more than 1 type of antibody. •There are 5 different kinds of antibodies that vary in the types of antigens they bind to form antibody/antigen complexes. They render antigens inactive by blocking their ability to bind to receptors, clumping them, causing them to precipitate or preparing them for phagocytosis. •A primary response is the initial exposure to an antigen that is usually mild. A secondary response after a second exposure occurs due to memory and produces a quicker and stronger response. •Stem cells differentiate into 4 types of T-cells: T regulatory, T helper cells (CD4), T memory and T effector (Tc). Tc (cytotoxic T cells) kills cells via apoptosis, particularly cancer and virus cells. •Maternal IgG protects a newborn for about 6 months until the newborn produces enough IgG on its own. •The thymus gland shrinks in the elderly which decreases its potential to assist in T-cell differentiation and ability to respond.

IgE antibodies

•allergic reactions and defense against parasites

Antigens

•are substances foreign to the host that can stimulate an immune response (immunogens). •Bacteria •Fungi •Viruses •Protozoa •Parasites •Nonmicrobial agents

T Lymphocytes

•formed in bone marrow and mature in the thymus gland •Activate other T cells and B cells •Control intracellular viral infections •Reject foreign tissue grafts •Activate autoimmune processes •Active delayed hypersensitivity reactions

IgD antibodies

•involved in B lymphocyte differentiation

Secretory lymph organs

•pockets of lymphoid tissues around membranes of digestive, respiratory and urogenital tracts

IgG antibodies

•protect against bacterial and viral infections (maternal/child transfer), present in all body fluids, most abundant

IgA antibodies

•protects immunoglobulins found in epithelial cells from degradation, prevents attachment of viruses to epithelium, present in saliva, tears, colostrum, and other secretions

Memory T Cells

•remain inactive until exposed to the same antigen, which then turns them into cytotoxic T cells (Tc)

B and T Lymphocytes

•—Cells that specifically recognize and respond to foreign antigens (memory) •B cells--Humoral immunity T cells--Cell-mediated immunity

Cell-Mediated Immunity or Cellular Immunity

•—T lymphocytes •Mediated by specific T lymphocytes •Defends against intracellular microbes such as viruses

Humoral Immunity

•—antibodies formed from B lymphocytes •Mediated by molecules in the blood •The principal defense against extracellular microbes and toxins •Create antibody-antigen complexes