Definitions Flashcards
HUMORAL IMMUNE SYSTEM
Component of the immune system that resides in the serum (not the difference between serum and plasma)
aka antibodies.
CELL MEDIATED IMMUNE SYSTEM
White blood cells (until mid session exam, consider ALL blood cells in this category)
INNATE IMMUNITY
NON-SPECIFIC
Immune system you’re born with. First line of defence, general protection. Neutrophils, NK cells etc.
Both humoral and cell mediated immune systems have an innate and an adaptive component.
ADAPTIVE IMMUNITY
SPECIFIC
Response to a specific pathogen. Improves with repeat encounters with the same pathogen.
Memory component. B and T lymphocytes etc.
Both humoral and cell mediated immune systems have an innate and an adaptive component.
LYSOZYMES
An enzyme which targets peptidoglycan in gram positive cell wall.
CYTOKINES
Soluble proteins or peptides which are like mobile phones for immune cells. If a cell needs to communicate with another cell it will release a particular type of cytokine. Only cells with the receptor for that particular cytokine will be able to respond to it.
(Like dialing a particular number and only the person with that number can pick up)
Eg. Interferon
APCs
Antigen Presenting Cells
MHC
Major Histocompatibility Complex. Membrane proteins that serve as peptide display molecules for recognition by T lymphocytes. Two types: MHC class I and MHC class II.
ANTIGEN (Ag)
Any molecule(s) that can be specifically RECOGNISED as being foreign (via receptors) by B cells, T cells or Ab. It may or may not induce an immune response.
EPITOPE
The portion of an antigen which is recognised (via receptors) and bound by immune system (B cells, T cells or an antibody).
Also referred to as “antigenic determinants”
3 categories:
- Isotype (constant region same within species)
- Allotype (constant region varies within species - multiple alleles)
- Idiotype (Variable region)
CLONAL SELECTION
The process by which particular lymphocytes (clones) are activated.
Antigen selectively causes activation, proliferation & differentiation of members of a clone of T or B cells that are specific for the antigen.
PHAGOCYTOSIS
The uptake of particulate materials by cells by engulfment.
STEPS:
1. Chemotaxis andAdherence
2. Pseudopodia encircle pathogen and fuse together, formation of phagosome which fuses with lysosome.
3. Ingested material is broken up into pieces and contents are eliminated via exocytosis.
*REMEMBER - some of the contents is retained and presented to T cells in the context of MHC II.
PHAGOCYTES
Cells with the capacity to internalise & degrade microbes or particulate antigens (neutrophils & macrophages are main phagocytes).
NEUTROPHIL
A phagocytic granulocyte involved early in the inflammatory response; most numerous WBC.
MACROPHAGE
Large mononuclear cells that phagocytose & kill micro-organisms, secrete cytokines & present antigens to T helper cells.
LYMPHOCYTE
A mononuclear leukocyte that mediates humoral or cell mediated immunity. Two types: B and T cells.
ANTIBODY (Ab)
Immunoglobulin (Ig), serum molecules produced and secreted by B cells (called plasma cells) in response to an antigen (Ag).
They are glycoproteins (A CHO component and a protein component)
COMPLEMENT
A group of serum proteins that participate in an enzymic cascade, ultimately generating the cytolytic membrane attack complex (MAC).
Major effector of HUMORAL branch of immune system because it is found in the serum component of blood.