Pathophys Exam 2

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Organs of the immune system
- bone marrow
- thymus
- spleen
- lymph nodes
Cells of the immune system
- Tcells
- Natural Killer Cells
- B Cells
- Granulocytes
- Macrophages
- Dendritic cells
Two types of T-cells and location
- CD4 and CD8
- liver
- blood intestinal and reproductive tracts
Helper T Cells
- CD4
- coordinators of immune regulation
- potentiate immune response
Killer T cells
- CD8
- important for directly killing tumor cells, viral infected cells and parasites
- down regulation of immune response
Natural Killer Cells
- directly kill certain tumors and viral infected cells.
- Stimulated by T-cells
B-cells
- responsible for production of antibodies
- adaptive response
- occurs under direction of CD4 cells
Granulocytes
- Neutrophils, Eosinophils & Basophils
- Removal of bacteria and parasites from the body.
Macrophages
- Antigen Presenting Cells
- Present to T and B cells
Dendritic Cells
- originate in bone marrow
- Antigen presenting cells (more efficient)
- Presents antigens to lymphoid organs
Innate Immune Response Components
- Physical barriers
- Biochemical messengers
- Cellular components
Duties of the innate immune response
- distinguish self from not-self
- Bind pathogens to PRRs on leukocytes to initiate signaling
Pattern recongnition receptors (PRRs)

host pathogen sensors that recognize structural patterns.
PAMPs

Pathogen associated molecular patterns
Toll-like receptors (TLRs)
- expressed on immune system cells responsible for innate response
- binding triggers recruitment of soluble mediators
Soluble mediators of innate immunity
- opsonins
- inflammatory cytokines
- acute-phase proteins
Opsonins

Tag pathogens for removal by phagocytosis
Inflammatory Cytokines
- stimulate recruitment of WBC
- stimulate acute-phase protein production
- inhibit viral replication
- affect development of innate and adaptive cells
- short half life
Cytokines that mediate innate immunity
- Type I interferons
- Tumor necrosis factor-A
- chemokines
Cytokines that mediate adaptive immunity
- interferon g (type II)
- lymphotoxin-a (TNF-B)
Acute phase proteins
- produced by the liver in response to cytokines
- inhibit microbial growth
- promote inflammatory response
- C-reactive protein
Complement system
- inactive precursor proteins that are present in circulation
- activated by pathogens, cytokines or antibodies
Three step reaction of the complement system
- Activation
- Amplification
- Membrane attack response
Complement protein mechanism
- complement binds antibodies on the pathogen
- attach to pathogen membrane forming a membrane attack complex
- MAC forms a pore in the membrane leading to cell lysis
Adaptive Immune System
- mobilized by cues from innate response
- discriminates between foreign and self
- responds to previously encountered antigens
- humoral and cell mediated immunity
CD4 and CD8 Cells recognize...

peptide complexes provided by antigen presenting cells
CD8 and CD4 cells secrete IL-4 and IL-5 which result in

B-cell proliferation
have not previously encountered an antigenfunction is antigen recognition

Naive lymphocytes
capable of performing the functions required to eliminate microbes. secrete cytokines.
- effector lymphocytes
- B lymphocytes
long-lived functionally silent cells which mount rapid responses to antigen challenge

memory lymphocytes
activates complement and binds to macrophages

IgG
primary defense against local infections in mucosal tissues

IgA
activates complement

IgM
Needed for maturation of B cells

IgD
Binds to mast cells and basophils

IgE
Two ways T cell receptors may recognize antigens
- presentation by MHC
- direct recognition of peptide fragments
MHCII goes with

CD4
MHCI goes with

CD8
MHC Class I produced in

the cytosol by the proteosome
MHC Class II expressed on
- specialized antigen presenting cells
- bacterial
stabilize interaction between t cells and MHC

adhesion molecules
When interaction between T cells and MHC then....
- a second signal is produced
- lack of production of the second signal results in apoptosis
3 major variables determining outcome of MHC/T-cell interaction
- duration and affinity of interaction
- maturity of T-cell
- nature of APC
T-cell differentiation and effector function driven primarily by
- IL-2
- niave to effector
Abilities of effector T cells
- lower activation threshold
- no costimulation required
- scan tissues that lack APCs
- gain access to peripheral tissues
Effector tcells _____ antigen bearing cells and activate _____.
- lyse
- phagocytosis
Memory B cells distribution in peripheral tissues is an example of

humoral immunity
Cells that hold immune system memory
- memory T cells and B cells
- low antigen stiumlation threashold
White blood cell count

increased number = infection
Mature neutrophils normal range (segs)

50-70%
immature neutrophils (bands) normal range

3-5%
Absoulte Neutrophil Count

WBC (%segs + %bands) divided by 100
ANC <1800

neutropenia
ANC<500

infection high risk
bacterial infections show

increased neutrophils (left shift)
viral infections show

increased lymphocytes
allergic reactions or protozoal infections show

increased eosinophils
Stress may cause
- delayed production of antibodies
- suppressed T cell activity

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Rx2013

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Card Set

Pathophys Exam 2

Description

Principles of Infectious Disease

Updated

2010-10-31T00:51:23Z

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