Exam 1: Immune/Inflammatory response Flashcards
What is the purpose of the immune system?
- Neutralize, eliminate, or destroy microorganisms that invade the body
- To recognize and eliminate aberrant cells (i.e. cancer)
Differentiate self vs non self—why is this important?
• Immune system cells only mount a response against cells determined to be “non-self”
o Cells different from a person’s own healthy cells
• Self-tolerance: the ability of cells to recognize self vs non-self
What are the main cells of the immune system?
• Leukocytes (WBCs)
o Neutrophils, Eosinophils, Basophils, Macrophages & Monocytes, Dendritic cells, NK cells, T cells, Cytokines, B cells, Complement
What factors influence the immune system?
- Nutritional status
- Environmental conditions
- Medications
- Presence of diseases
- Age
What are the three processes involved in immunity? Which are specific vs nonspecific
• Nonspecific
o Inflammation
• Specific
o Antibody-mediated (humoral) immunity
o Cell-mediated immunity
What are the components of the immune system
• Skin and mucous membranes • Mononuclear phagocyte system • Lymphoid system o Spleen, thymus gland, and lymph nodes • Bone marrow
Identify the cells of the immune system: lymphoid
B cells
• Major cells of antibody-mediated immunity
• Able to produce antibodies
• Require help from T helper cells to respond
T cells
• Major cells of cell-mediated immunity
• T-helper cells (CD4+)
• Interact with antigens
• Secrete cytokines that stimulate B-cell proliferation and antibody production
NK cells
• Innate immune cells
• Can kill tumor cells and virally infected cells without previous exposure
Identify the cells of the immune system: myeloid
RBCs
• Erythrocytes, deliver oxygen to the tissues, iron rich hemoglobin binds to oxygen
Monocyte
• Immature macrophages
• Circulate in the blood stream for about 3 days prior to entering tissue and becoming macrophage
• Macrophages
o Called different cells in different tissue
o Life span from months to years
o Functions
Phagocytosis
Repair of injured tissue
Antigen processing (CD4+)
Secretion of cytokines to help control the immune system
Granulocytes
• Neutrophils
o 60-80% total
o Stem cells – mature in bone marrow
o Mature: segmented neutrophils (segs)
o Immature: (bands)
o 1st responder to infection
o No energy reserve (6 hour life span)
o Only mature form (segs) capable of phagocytosis
o Produce potent chemical mediators that enable them to destroy microorganisms
• Eosinophils
o Allergic reactions and infection by intestinal parasites
o Release inflammatory chemicals in areas of inflammation
o Primary function to kill parasitic helminths (worms)
• Basophils
o Release vasoactive substances (heparin, histamine) during inflammation
o Also involved in wound healing
Why are neutrophils important?
1st responders to infection
What are macrophages and why are they important?
• Carry out phagocytosis to destroy foreign invaders
What is complement?
- 20 plasma proteins that interact in a cascade fashion to produce important mediators of inflammation and immunity
- Can be activated by microbial agents (alternative pathway) or by antigen-antibody complexes (classical pathway)
What is the process of inflammation?
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What are the clinical manifestations; local and systemic
• Systemic o Fever o Neutrophilia (increased WBC) o Lethargy o Malaise o Increased acute phase proteins (CRP) o Increased erythrocyte sedimentation rate (ESR or sed rate) • Local o Redness, swelling, heat, pain
What cells are important to the process?
• Neutrophils, eosinophils, NK cells, macrophages
Identify nonspecific vs specific components of the immune system
• Specific adaptive immunity
o Acquired through previous exposure to infectious and other foreign agents
o Destroy specific foreign agents based on their distinct antigenic properties
o Recognizing foreign invaders, destroying them, and retaining a memory of the encounter such that an even more effective defense (adaptive) will be achieved upon subsequent exposure
o B and T lymphocytes are mediators
o B cells “humoral” immunity because the antibodies they produce are found in body fluids
o T cells produce cell mediated because they recognize antigens
• Nonspecific innate immunity
o Cellular and biochemical defenses that are in place before an encounter with an infectious agent
o Provide rapid protection
o Able to distinguish between self and non-self but not specific agents
o Major components
Epithelial cells: block entry and secrete antimicrobial enzymes
o Phagocytic neutrophils and macrophages
Engulf and digest microbes
o Dendritic cells (DCs)
o NK cells
Kill intracellular microbes and foreign agents
o Complement system
Amplifies the inflammatory response
Where do B and T cells mature?
- B cells – bone marrow and lymph tissues
* T cells – thymus
What is the MHC?
- Cluster of genes on chromosome 6
- Also known as human leukocyte antigen (HLA) complex
- Proteins made by these genes are displayed on the surface of body cells and mark them as “self”
Describe the process of antibody mediated immunity listing the main cells involved
• Memory B cells
o Contain antigen receptors and function in manner similar to memory T
o When exposed to the same type of antigen, respond rapidly with antibodies
• Plasma cells
o Short-lived antibody producing factories
o Have receptors on their surfaces that can bind antigens
o Each B cell binds only one particular antigen
• Long lasting immunity possible
What happens during and antibody-antigen interaction?
• Antibodies are proteins that specifically bind a particular antigen
• Antibodies have several functions
o Precipitation
o Agglutination: form large insoluble complex
o Neutralization: toxins bound or inactivated before they can interact with cells
o Opsonization: foreign antigen is coated making it more recognizable to phagocytic cells (happens in the spleen)
o Complement activation
How is immunity achieved?
- B and T cell functions are interdependent
- T cells cannot respond to soluble antigens
- On first exposure, B cells are minimally activated by antigen unless they are stimulated by cytokines from T cells
- Immunity = state of resistance against infection from a particular pathogen
- Provided primarily by adequate levels of circulating antibodies
What are the 5 immunoglobulins and where are they found
• IgG o Most common o Complement, crosses placenta • IgM o Activates complement o ABO incompatibility (blood typing) • IgA o Secretions (mucus, saliva, tears, breast milk) • IgD o Stimulates B cells to multiply and mature • IgE o Parasites and respiratory infections o Hypersensitivity reactions
What is innate vs adaptive immunity?
- Innate (natural) – in place before encounter, not specific
- Adaptive (acquired) – through previous exposure, specific
What is Active vs passive immunity?
• Active o Acquired through actually having the disease o Antigen enters the body and antibodies are created against it o Natural active Person has disease Most effective and longest lasting o Artificial active Small amount of antigen introduced Vaccinations, may require boosters • Passive o Temporary type transferred (in utero, breast milk) o Antibodies introduced into the body o Natural passive Mother to fetus across placenta o Artificial passive Antibodies injected When person is exposed to a serious disease and has no known actively acquired immunity Rabies, snake bite, tetanus
Define this alteration in immune function: autoimmunity
• Inappropriate immune response; lack of differentiation of self
• Body attacks own tissue
o Recognizes self-cells as foreign and mounts an immune response that injures self-tissue
• Polygenic and multifactorial
Define this alteration in immune function: hypersensitivity
• Exaggerated or inappropriate response to specific antigens; overresponsiveness
•Define this alteration in immune function: immunodeficiency
- Lack of a response by a component of the immune system
* Due to missing component, damaged component, or missing step in parts of the immune system
Define this alteration in immune function: malignancy of WBC’s
• Cancer of WBCs (Leukemia, lymphoma, plasma cell myeloma)
Know the four types of hypersensitivities, patho and examples
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Primary immunodeficiencies patho
IGA disorder
- Most common
- Familial, resulting in no circulating or secretory levels of IgA
- May be acquired, caused by medications or various diseases
- Chronic infections of the sino-pulmonary tract, GI tract, and GU tract
- Treatment: treat infections w/ antibiotics
Primary immunodeficiencies patho: Bruton X-Linked
- Males, females are the carriers
- Immature B-cells unable to produce antibodies
- Decreased IgG, IgM, and IgA
- No apparent health problems until 4-5 months (protected by IgG from mother)
- Recurrent infections: ear infections, dermatitis, pharyngitis, bronchitis, pneumonia, etc
- Treatment: Antibiotics (chronic, low-dose), IV Ig (passive immunity w/ antibodies
Primary immunodeficiencies patho: DeGeorge’s syndrome
- Lack of development of thymus gland’ aplastic (doesn’t work) or hypoplastic (reduced function)
- T cells can’t mature
- Congenital (random mutational event)
- Associated with other developmental disorders: heart defects, hypoparathyroidism hypocalcemia (tetany)
- Severe recurrent infections: viral, fungal, protozoan, and bacterial
- B-cell levels may be normal, but may have abnormal antibody response due to decreased helper T cells
- Treatment: antibiotics/anti-infectives
Chronic Mucocutaneous Candidiasis
• Autosomal recessive causing selective T-cell response
o Normal T-cell response to non-fungal pathogens
o Cannot respond to Candida
• Normal antibody responses
• Accompanied by endocrine dysfunction, parathyroid and adrenal glands
SCID
- Severe Combined Immune Deficiency Syndrome
- Inherited X-linked
- No immune system: lack B and T cells
- Severe recurrent infections and/or neoplasms
- Cannot live outside sterile environment
- Treatment: bone marrow transplant or gene therapy
Define HIV, what is the patho, and define the cells primarily infected
• Human immunodeficiency virus
• AIDS = Acquired immunodeficiency syndrome
• Defective cell-mediated immunity, especially decrease of CD4 or helper T cells
• Caused by retrovirus
• Retroviruses infect human cell and reverse transcriptase (enzyme) forces human DNA to use viral RNA
• This new DNA is incorporated into the human cell’s DNA and is now template for viral replication
• HIV attaches to and infects helper T cells and macrophages
• At risk for opportunistic infections and tumor formation
• Found in all body fluids, transmitted through blood, semen, vaginal/cervical secretions, amniotic fluid, and breast milk
• Classification based on CD4 counts
o >500 ul
o 200-400 ul
o
