12.8 immunology Flashcards
2 WAYS PATHOGENS CAUSE HARM/DISEASE
- Produce toxins which can directly damage tissue
- Replicate inside and destroy host cells
Each type of cell has specific molecules on its plasma cell surface membrane to identify it.
They can identify:
- Pathogens
- Cells from other organisms of the same species
- Abnormal body calls
- Toxins
- pathogenic bacteria will have different proteins in their cell membrane to our proteins
- our immune system can detect these different molecules and make antibodies against them (with complementary shape)
Antigen definition
and examples
A molecule that stimulates an immune response that results in the production of a specific antibody
EXAMPLE - GLYCOPROTEINS AND GLYCOLIPIDS
what is phagocytosis
non-specific immunity
They are a group of white blood called which can distinguish between cells which do or do not display the self antigens>
They will ingest / engulf and destroy any cell that presents a non-specific antigen
key points of phagocytosis
1+2) Pathogen is engulfed by phagocyte
3) Engulfed pathogen enters the cytoplasm of the phagocyte in a vesicle which is now called a phagosome
4) Lysomes fuse with phagosome releasing hydrolytic digestive enzymes
5) enzymes hydrolyse the pathogen
6+7) waste materials are released from the cell by exocytosis and antigens presented on the cell surface membrane and the phagocyte becomes an antigen presenting cell.
HOW PHAGOCYTIC WHITE BLOOD CELLS DESTROY BACTERIA
- Phagocyte attracted to by chemicals / recognise antigens on bacteria as foreign
- Engulf / ingest bacteria
- Bacteria in vacuole / vesicle
- Lysosomes fuses with / empties enzymes into vacuole
- Bacteria digested / hydrolysed
TH CELL (HELPER) FUNCTION
- Specific Th cell binds to the antigen presenting cell
- releasing cytokines that attract phagocytes to the area of infection
- Release cytokines that activate cytotoxic killer T cell
- Activates a specifically complementary B cell
- Form memory T cells
TC CELL (CYTOTOXIC KILLER T CELL)
Locate and destroys infected body cells that present the correct antigen
Binds to antigen-presenting-cells
Releases perforin (protein) which creates holes in the cell surface membrane which destroys the APC.
EXPLAIN B CELL ACTIVATION
- Specific Th cell binds with correct receptor binds to presented antigen and the locates and activates a specifically complementary B cell. Specific Th releases cytokine chemicals that signal the specific B cell to clone by mitosis.
- The B cell then differentiates into two types of cell:
- Plasma cells - produce and secrete vast quantities of specific antibodies into the blood plasma
- Memory (B) cells - remain in the body to respond to pathogen rapidly and extensively should there be a future re-infection.
Describe how the human immunodeficiency virus (HIV) is replicated once inside t helper cells
- RNA converted into DNA using reverse transcriptase
- DNA incomperated into (T helper cells)
- DNA transcribed into RNA
- Translated into HIV /
protein
What is the humoral response
Involves the activation of B cells to produce antibodies B cells must be stimulated by their their complementary Th cell by the release of cytokines
Antibodies
protein made in response to frein antigen has binding sites which bind specifically to an antigen.
A specific antiboy is produced by a specific plasma cell
AGGLUTINATION MEANING
Specififc antibodies binds bind to the antigens on pathogen and clump them together
OPSONISATION meaning
marking pathogens so phagocytes recognise and destroy the pathogen more efficiently
LYSIS
Bind to antigens and lead to destruction of the pathogen’s membrane
