Foundations In Immunology Flashcards
Innate immune cells
Macrophages and neutrophils
Adaptive immune cells
Lymphocytes
Innate immune system
The first line of defence. There are physical barriers; tight junctions between epithelia and mucous membranes. Phagocytic cells; macrophages and neutrophils. And soluble factors.
Natural killer cells
Provide protection against viral and bacterial infections and they help detect and limit the development of cancer. They secret cytokines which are used for lysis or apoptosis. They can recognise non-self cells due to presence of MHC 1 (major histo-compatibility antibody) which presents peptide fragments of non-self proteins.
Phagocytosis
Triggered when the phagocyte recognises a foreign cell. It is ingestion of foreign matter by cells into cytoplasmic vesicles. Once inside, the matter is digested by enzyme containing lysosomes. It also kills the cell that did the ingesting.
Primary lymohoid organs
Thymus, bone marrow and foetal liver. The generation and training of lymphocytes.
Secondary lymphoid organs
Lymoh nodes and spleen. Initiates immune responses and maintains lymohocytes.
Fundamental properties of an adaptive immune system
Specificity, diversity, memory, recruitment of other defence mechanisms.
B-lymphocytes
B cells differentiate to form plasma cells and then antibodies for use against the pathogen. The pathogen is first recognised by membrane bound antibodies. The antibodies produced by plasma cells are soluble in plasma.
Antibodies
IgM - opsonisation
IgG - good opsoniser
IgA - protects mucosal surfaces, resistant to stomach acid.
IgE - defends against parasites, causes anaphylaxis and allergies.
Interaction of antigen presenting cells and T-lymphocytes
The antigen presenting cell presents to T-helper cells which attach to/highlight the foreign body and communicate to T-killer cells and B cells.
Complement system
25 serum proteins.
The sequential activation and assembly into functional units bring about 4 events;
1. Recruitment of inflammatory cells (mast cells and neutrophils)
2. Tagging/opsonisation of bacteria to promote phagocytosis.
3. Lysis of bacteria
4. Stimulate activation of B cells and antibody production.
Classical pathway; antigen:antibody complex
MB-Lectin pathway; lectin (sugar) binds to pathogen surfaces.
Alternative pathway; pathogen surfaces.
Cytokines
Chemicals used by cells to communicate with other cells.
T-helper cell 1
Thc 1 contribute to the cellular response and recruit macrophages and neutrophils. Cell mediated and phagocyte dependant immunity.
CD8-Thc1 = 8
T-helper cells 2
Thc 2 contribute to the humoral response and produce antibodies and eosinophil activation.
CD4-Thc2=8
