Immune system pathologies Flashcards
Innate Immunity
- non-specific (no memory cells)
- no immunological memory
- includes first and second lines of defense
- ex: epithelial barriers, phagocytes, dendritic cells, complement cascade, Natural killer cells
First line of defense
- part of innate immunity (non-specific)
- skin
- nasal hair
- ear wax
- reflexes
- mucosa (digestive system, lungs, reproductive organs)
- secretions: tears, sweat, saliva
Second line of defense: cellular components
- internal defenses inflammation and repair
- innate non specific immunity
- cellular components
- WBCs
- monocytes
- macrophages
- eosinophils
- basophils
- platelets
- mast cells
- natural killer cells
- erythrocytes
Second line of defense: soluble components (plasma proteins)
- clotting factors
- complement system (lysis)
- protein factors that break down cell membranes of antigens
- kinin system (vasodilation)
- chemokines
- cytokines (interferons, interleukins, tumor necrosis factor)
- part of innate and adaptive immunity (some overlap)
Third line of defense
- adaptive immuntiy
- specific
- immunological memory
two types: - humoral (B-cells) antigens and antibodies
- cell mediated (T-cells) antigens and T -lymphocytes, T helper cells CD4+ and CD8+
Antigen
- what you are exposed to and need an adaptive response to
- foreign substance such as bacteria, virus, parasite, foreign tissue, large protein
- elicits immune response; acquired immunity
Antibodies
- formed by B cells
- polypeptide chains called globulins
- also called immunoglobins
Jobs of antibodies/immunoglobulins
- attack, destroy, neutralize antigens
- activate the complement (lysis) system
- release histamine (anaphylaxis)
- stimulate anti-body-mediated hypersensitivity
Cell-mediated adaptive immunity
- T-cells from thymus gland learns about antigens from other cells as they circulate through lymphatic system and spleen
- different receptors form on cells
- can attack intracellularly and extracellularly
- types of T-cells: CD4+ and CD8+
- more likely to get sick with decreased CD4+
function of
1. B lymphocyte
- neutralization of microbe, phagocytosis, complement activation
Help T cell function
- activation of macrophages;
- inflammation
- activation of T and B cells
function of
5. natural killer cell
- killing of infected cells
Exercise effect on lymphocytes
- brisk exercise increase the WBC count in proportion to the effort
- lymphocytes increase during exercise but decrease below the normal levels for several hours after intense exercise
- the effects of intense exercise on secondary antibody response in older adults remain unknown
exercise and infection
- exercise during the incubation period of infection appears either to have no effect or to increase the severity of infection
COVID-19 testing
Antigen testing:
- determine presence of antigen proteins
- will be positive while virus or baceria is present
PCR: polymerase chain reaction
- detect genetic material from COVID-19
Antibody test:
- been exposed but not sure when or if infection is currently happening
- tests for presence of antibodies (IgM, IgG) produced in response to previous infection
Aging and the immune system: immunosenescence
- aging is accompanied by immune dysregualtion as immune function declines with increasing age
- this is described as oxidative (free radical) theory of aging
Changes in innate immunity with age
- exterior defenses are affected by thinning of skin
- phagocytes: neutrophils and monocytes/macrophages show decreased function with aging
- eosinophils accumulate in fewer numbers as sites of infection with age
- basophils are characterized by reduced degranulation with aging
Changes in acquired immunity with age
- older adults have decreased response to newly encountered antigens
- depends on naive T and B cells that decline in production with age
- decline in antibody production that may be due or inappropriate or insufficient T-cell help
Exercise immunology- how does moderate exercise and strenuous exercise affect the immune system
- immune system is enhanced during moderate exercise
- regular moderate physical activity can prevent the neuroendocrine and detrimental immunological effects of stress
- strenuous or intense exercise or long-duration exercise such as marathon running may be followed by impairment of the immune system
how does exercise effect neutrophils and macrophages
- exercise triggers a rise in blood levels of neutrophils (PMNs) and stimulates the phagocytic activity of neutrophils and macrophages
- if exercise goes beyond 30 minutes a second or delayed rise in PMNs occurs
- this delyaed rise is probably result of cortisol
how does exercise effect natural killer cells
- number of NK cells increase
- function or activity of NK cells increases
- during and immediately after exercise
NK enhancement: - temporary
- surge in epinephrine (reduce inflammation and fights some infection)
- after intense exercise of long duration, the concentration of NK cells and NK cytolytic activity declines below pre-exercise values
Exercise and apoptosis
- it is surmised that exercise-induced apoptosis is a normal regulatory process that removes certain damage cells without a pronounced inflammatory response, thereby ensuring optimal body function
what are hypersensitivity disorders
- overreaction to a substance or hypersensitivity
- often referred to as allergic reaction
- although the term allergy is widely used the term hypersensitivity is more appropriate
What are the types of hypersensitivity disorders
- immediate
- late phase
- delayed
immediate hypersensitivity disorder
- reaction occurs within minutes of exposure
- hay fever, allergic rhinitis(nasal passage only), urticaria (hives), extrinsic asthma (exposure to something in the air) and anaphlactic shock)
- may be a hereditary disposition
immediate response: - histamine release
- other inflammatory mediators enhance and prolong the response initiated by histamine
late-phase hypersensitivity disorders
- inflammation and symptoms persist for hours to days after allergens are removed
- can cause cumulative damage
delayed hypersensitivity reactions
- occurs after sensitization to certain drugs or chemicals
- can take several days to cause symptoms
- ex: poison ivy, penicillin allergy)
What happens if an immediate hypersensitivity becomes systemic
- widespread release of histamine
- systemic vasodilation, bronchospasm, increased muscus secretion and edema
- referred to as anaphylaxis
Anaphylaxis
- life-threatening emergency and requires immediate intervention with injection epinephrine to restore blood pressure, strengthen the heartbeat and open airways
- an increase in the prevalence of atopic disease (hypersensitivity) has occured in US during past 2 decades
type 2 hypersensitivity
- cytotoxic reactions to self-antigens
- the body’s own tissue is recognized as foreign or nonself
- autoimmune disease
Type 3 hypersensitivity
- immune complex disease
- when antigen-antibody complexes (immune complex) circulate in the blood
- initiates inflammation and tissue injury
- resulting in vasculitis
what are examples of vasculitis
1. urticaria
2. synovitis
3. nephritis
4. pleuritis
5. pericarditis
- skin: urticaria (wheals and hives
- joints: synovitis
- kidneys: nephritis
- pleura: pleuritis (heart or lung pleura)
- heart: pericarditis
Type 4 hypersensitivity
- cell-mediated immunity
- delayed response
- antigen is processed by macrophages, presented to T-cells
- Sensitized t-cells release cyokines which recruit lymphocytes, monocytes, macrophages and PMNs
what are some examples of a delayed response with type 4 hypersensitivity
- contact dermatitis after exposure to an allergen
- response to Tb test
- graft-versus-host disease and transplant rejection
function of cytotoxic t lymphocyte
killing infected cells
function of regulatory T lymphocyte
suppression of immune response
