Jan. 17th (Exam 1) Flashcards
What is innate immunity?
It is the host defense mechanisms that act at the start of an infection.
Describe the timeline of events of what would happen regarding our innate immunity during the interaction of a bacterium and the complement system and subsequent activation of effector cells.
The bacteria’s surface will induce cleavage of the complement system and one of the fragments of the system with covalently bind with the bacterium.
The other fragment of the complement system will attract the effector cell.
Then the two fragments will attach and the effector cell engulfs the bacteria, kills it and breaks it down.
What will effector cells produce as they start to engulf bacteria?
Cytokines
What are cytokines?
Soluble proteins that are produced by cells to affect the behavior of surrounding cells.
i.e they are made when cells detect infection, and they react with other cells to trigger innate immune response.
What else do cytokines do regarding the blood vessels?
Specific cytokines cause vasodilation and make the blood vessel leaky so that fluid, proteins, and inflammatory cells to leave the blood and enter the tissue.
What are the four characteristics of inflammation?
- Heat - (Calor)
- Pain - (Dalor)
- Swelling - (Tumor)
- Redness - (Rubor)
What is the word for swelling we use in healthcare?
Edema
What are inflammatory cells?
These are the WBCs that are present in inflamed tissue that contribute to the inflammation via the cytokines they produce.
Define the Adaptive (acquired) immune response.
The adaptive immune response is the dynamic immune response of ANTIGEN SPECIFIC B and T lymphocytes to antigens involving the development of an immunological memory
List the different lymphocytes and briefly describe them.
- B-cells (small agranular)
- T-cells (small agranular)
- NK cells (large granular)
Define antigen. What are some things that could be considered an antigen?
An antigen is a molecule or molecular fragment that can be recognized by antibodies, B, or T cells.
Antigens could be a protein, part of a protein, a glycoprotein on the surface of a pathogen etc. etc…
B-cell have immunoglobulins that allow them to recognize antigens.
What is the similar apparatus in T-cells?
T-cell receptors.
In what way is the adaptive immune system adaptive to the pathogen?
The cells of the immune system that are best suited to recognize the antigen present on a particular pathogen are selected for and proliferate in masse to fight the infection.
What is the adaptive immune system unique to?
Vertebrates
What are the characteristics of the innate immune system used in our comparison of Innate Vs. Adaptive?
- Fast response
- Will NOT change depending on the pathogen
- Very limited in what it is able to do
- Constant, invariable, response during the entire duration.
What are the characteristics of the adaptive immune system used in our comparison of Innate Vs. Adaptive?
- Slow response
- Variable type of response - depending on the type of pathogen, different cells can be recruited.
- Highly specific in what it is able to do (many options)
- Response can change during the course of the response - as more and more specific cells are selected for, it will only get better.
How do we get different lymphocyte receptors?
They are encoded by genes that are spliced, cut and modified during development.
What is clonal selection?
This is the process of stimulating a small number of specific, pathogen-oriented lymphocytes for proliferation.
What is clonal expansion?
This is the process of proliferation and differentiation of selected lymphocytes.
What are memory cells?
These are the cells that are selected for during an adaptive immune response that may persist after the infection.
Describe the concept of immunological memory.
Infections after the primary response by the same pathogen may cause a stronger and faster adaptive immune response.
Define acquired/protective immunity.
The adaptive immunity is that protection provided by immunological memory.
What is the primary immune response?
This is the first interaction that the immune system has with a pathogen.
What is the secondary immune response?
This is any encounter that we have with a pathogen after the primary response.
What is required to activate the adaptive immune response?
The innate response.
Is the innate response or the adaptive response more important, generally speaking?
The innate.
Vaccines must induce only/both the innate immune response and adaptive immune response.
BOTH
What is the process of making WBCs, RBCs and platelets?
This is called Hematopoiesis.
Describe what pluripotent hematopoietic stems are and what they can do.
These are where all WBCs, RBCs and platelets come from; they are highly undifferentiated.
They can either self-renew or they can differentiate into more mature hematopoietic cells.
What cells do platelets come from?
Describe their physical characteristics.
They come from Megakaryocytes.
They have giant nuclei.
During the timeline of human life, when does hematopoiesis occur?
- It occurs early in development in the yolk sac
- It occurs in the fetal liver and spleen starting at month 3 or 4 of fetal development
- It occurs in the bone marrow at about five weeks into fetal development progressively becoming more and more common and is the only way for the rest of the human’s life.
What did we generally define an immunoglobulin as?
We called it a non-secreted version of an antibody which is present on the surface of B cells.
What are the two general things that a hematopoietic stem cell can become?
- Common lymphoid precursor - all lymphocytes (B-cells, T-cells, NK cells)
- Common myeloid precursor - everything else!
What are the small lymphocytes?
What is characteristic about them?
These are our immature B cells and mature T cells
They have huge nuclei!
What are plasma cells?
What do they do?
These are the fully differentiated version of B-cells.
They make antibodies.
What are dendritic cells?
What can they do?
They are of monocyte origin (not lymphocyte).
They can active T-cells and initiate the adaptive immune response (think genetics)
What are NK cells?
They are from lymphocyte origin.
They will kill cells that are infected with certain viruses.
What are neutrophils?
These are granulocytes of myeloid origin and come from myeloblasts.
They phagocytize and kill microorganisms.
What are monocytes?
These are the precursors to macrophages for sure, and possibly dendritic cells.
- Myeloid origin*
What are eosinophils?
These are granulocytes that will kill antibody-coated parasites by releasing granules.
What are basophils?
They are granulocytes of myeloid origin that come from myeloblasts and they control the immune response to parasites.
What are megakaryocytes?
They are cells of myeloid origin that are important in platelet formation and wound healing.
What are granulocytes?
What are the three types?
They are a group of myeloid cells that contain cytoplasmic granules that kill microorganisms and enhance inflammation.
- Neutrophils
- Eosinophils
- Basophils
What is unique about granulocytes?
Their nuclei look weird.
They almost resemble a horseshoe.
Explain the role of neutrophils in the innate immune response.
We keep large reserves of them within the bone marrow to be released when we need to fight infection. They will travel to and enter the infected tissue once resident macrophages release cytokines to kill and engulf bacteria. They then die in the tissue and are engulfed and degraded by macrophages.
What are monocytes?
What is unique about them?
What are they the progenitors for?
They are myeloid immune cells that circulate in the blood and have an indented nucleus.
This shape is like an “almost horseshoe”
They are the progenitors for
1) Macrophages
2) Dendritic cells
Describe macrophages.
They are the “large phagocytes” and they are sedentary, and the scavenger cells of the tissue.
Describe Dendritic cells.
These are the mobile, star-shaped cellular messengers that can activate an adaptive immune response.
What are mast cells?
They are myeloid cells that are distinct in origin from the three granulocytes we talked about.
They are found in the connective tissue and contain granules.
They help in some way with allergies, but their main purpose is to fight parasites in one way or another.
