Readings Ch 1, 2, 17 Flashcards
What is herd immunity?
Decreasing number of people who can harbor and spread infectious agent decreases chances that susceptible people will be infected
What is Antiserum?
antibody containing serum from a pathogen-exposed individual
What is passive immunity?
Immune protection of an individual or passed between individuals that isn’t generated by the person’s own immune response to a pathogen
What is active immunity?
Production of one’s own immunity
What is the active immune system subdivided into?
Humoral (fluid) immunity
-Involves B Lymphocytes
Cell-Mediated immunity is immunity imparted by specific cells
-Involves T Lymphocytes
What is a lymphocyte and what are the types?
Lymphocyte is cell type responsible for cellular and humoral immunity
T Lymphocytes (T cells) - derived from thymus
B Lymphocytes (B cells) - derived from bone marrow
What is an antigen?
General term for any substance that elicits a specific response by B or T Lymphocytes
What does a B Lymphocyte (B cell) do?
Humoral immunity
- During innate response macrophages also present pathogenic antigens to B Cells
- B Cell receptor binds specific antigen to BCR
- B Cell calls helper T Cells that help the B cell differentiate into Plasma cells and Memory cells
- Plasma cell produces specific antibodies for antigen of pathogen and flag them for destruction
- Memory cells keep copy of antigen in case of reinfection
What does T Lymphocyte (T cell) do?
Cell-Mediated Immunity
- Helper T Cells do:
- Help B Lymphocytes mature into Plasma Cells and Memory Cells by releasing Interleukins
- Help turn T Cells into Cytotoxic T Cells which bind to infected cells and kill them
- Help turn T Cells into their own memory T Cells
It is difficult to detect pathogens once they are in a cell (viruses). How do we do this?
Cytotoxic T Lymphocytes (Tc Cells)
-Recognition molecules posititioned inside cells that detect changes that occur upon infection
What are PAMPs and how are they recognized?
Pathogen-Associated Molecular Pattern
- General term for common structures that characterize whold groups of pathogens (bacterial, viral etc)
- Non-specific, helps tailor immune response
Pattern Recognition Receptors (PRR)
- specifically recognize these PAMPs
- cause cascade to label pathogen for destruction
What is generation of diversity?
Rearrangement and editing of DNA for recognition molecules (PRR)
- Creates many variants of recognition molecule that can hopefully catch the constantly evolving antigens on pathogens
- Once it finds one it will make many copies and circulate through body
Generation of diversity creates possibility that a variant could attack the host. How do we avoid this?
Tolerance
- Newly developing B and T cells must first pass a test of nonresponsiveness against host
- Consequentially, immune system will ignore cancerous cells
What is the result of innate immunity?
Rapid Recognition and Phagocytosis
Destruction of pathogen
Why is adaptive immunity slower to respond?
Fewer cells possess the perfect receptor for the job
- antigen specific randomly generated receptors on B and T cells
- After encounter B and T cells undergo selection and proliferation
What is the goal of vaccination?
Development of specific and long-lived adaptive response (immunologic memory)
How do innate and adaptive immune systems communicate?
Cytokines
-recruit or instruct cells and soluble proteins important for eradication of the pathogen from within infection site
What are leukocytes and lymphocytes?
Leukocytes are blanket term for WBC’s
-Lymphocytes are 1 of 5 types of Leukocytes (WBC)
What are the three most common instances of immune dysfunction?
Hypersensitivity
Autoimmune Disease
Immune Deficiency
What is Hypersensitivity?
Overly zealous attacks on common benign but foreign antigens
What is Autoimmune Disease?
Erroneous targeting of self proteins or tissues by immune cells
What is Immune Deficiency?
Insufficiency of the immune response to protect agains infectious agents
Coordination of a full immune response is made possible by specialized anatomy of the immune system. What are the two categories of organs?
Primary Lymphoid Organs
- Bone marrow and Thymus
- Regulate development of immune cells
Secondary Lymphoid Organs
- Spleen and Lymphnodes
- Coordinate encounter of antigen with antigen-specific lymphocytes
- Coordinate their development into effector and memory cells
What is hematopoiesis?
Process by which Hematopoietic stem cells (HSC) differentiate into mature cells
What is the difference between embryonic stem cells and adult stem cells? What kind are HSC’s?
Embryonic stem cells
-can generate every specialized cell type in organism
Adult stem cells
-can generate any cell type that make up a specific tissue
HSC’s are adult stem cells b/c they can become any type of blood cell
What are the types of leukocytes and what is the ~% of each found in human blood?
Neutrophil 50-70% Lymphocyte 20-40% Monocyte 1-6% Eosinophil 1-3% Basophil <1%
During Hematopoiesis, what two types of progenitor cells can a Hematopoietic Stem Cell turn into? What can form out of each progenitor cell type?
HSC can turn into a Myeloid progenitor or a Lymphoid progenitor
Myeloid Progenitor
-Dendritic cell, Monocyte, Neutrophil, Eosinophil, Basophil
Lymphoid Progenitor
-Natural Killer Cells, B Cells, and T Cells
Granulocytes are at the front lines of attack during an immune response. Are they part of the innate or adaptive response and what are the types of granulocytes?
Part of the innate response
Types:
1) Neutrophils
2) Basophils
3) Mast Cells
4) Eosinophils
What are Neutrophils?
Granulocytes that are recruited to site of infection in response to inflammatory molecules (chemokines) and Phagocytose the bacteria.
What are Basophils?
Non-phagocytic Granulocytes that secrete cytokines and release histamines (swelling/redness)
What are Mast Cells?
Non-phagocytic Granulocyte like basophil. Secrete histamine. Important in development of allergies.
What are Eosinophils?
Motile Phagocytic Granulocytes that migrate from blood into tissues. Most important against parasites (worms).
What are Professional Antigen Presenting Cells (APC)?
Monocytes, Macrophages, and Dendritic Cells
- They are the bridge between innate and adaptive systems
- Make contact with pathogen at infection site and communicate this encounter to T cells in Lymph node (presentation)
What are Monocytes?
Migrate into tissues and differentiate into different phagocytic cells
-Inflammatory and patrolling monocytes
What are Macrophages?
Type of Monocyte that migrates into tissues. Acts a phagocyte or can present antigens
What are Dendritic Cells?
They capture antigen in one location and present it in another.
-Process these antigens and migrate to lymph nodes and present them to naive T cells, initiating the adaptive immune response
What occurs when a naive Lymphocyte (B or T cell) encounters an antigen?
This induces the naive lymphocyte to proliferate and differentiate into memory and effector cells.
- Memory cells persist in host and mediate a quicker response in future
- Effector cells carry out specific jobs to combat pathogen
What is a Natural Killer Cell?
Lymphoid cells closely related to B and T cells but without antigen specific receptors
-Attack and kill infected cells
