1. Innate Immunity Overview
The innate immune response is non-specific, then there is specific, adaptive immune response. This page is a brief outline of the components of innate immunity. For a review of cell types see: 2B. Innate Immune Cells
Levels of Defence
Non-specific and specific
- Non-specific barriers include
- Physical barriers - skin, mucus, cilia
- #Chemical Barriers - stomach acid, lysozyme in sweat, tears, etc
- Biological barriers - microbiota, reflexes, excretion, other mechanical barriers
Components of Innate Immunity
Skin
- Barrier of dead cells and keratin
- low PH: suboptimal conditions for bacterial life
- chemicals that disrupt viruses
- normal bacteria, microflora, "crowd-out" other bacteria
Inflammation
- breach in skin allows entry -> chemical released triggering the response
- increases temperature
- influx of macrophages to ingest antigens -> secrete lysosomes to break it up ->present antigen on cell surface
- attacks any non self cells, (hence non specific)
Antibodies
- antigens have specific proteins on their surface
- generally Y shaped with different "ends" (antigen binding site) that dock to antigens, allow them to be found by macrophages, and disrupt antigen function
- gaining specific immunity is essentially being able to produce these antibodies
B Lymphocytes
- made in bone marrow and responsible for humoral response
- humoral = in the "humours" or fluid e.g. blood, lymph, interstitial fluid
- Produce antibodies : naïve B calls sense the shape of the antigen -> produce antibodies -> produces specific memory B cells
T Lymphocytes
- responsible for cell mediated response, targets and kills cells within the body that are already infected
- made in thymus gland (above the heart)
- create killer T cells, activated T cells that identify virally infected self cells, dock to them and induce apoptosis
- In HIV T-Helper cells are the cells that are affected ![[Humoral and Cell mediated pathways.png]
Chemical Barriers
- include soluble substances with antimicrobial activity e.g. lysozyme, psoriasin, and other antimicrobial peptides (AMPs) and antimicrobial enzymes.
- acidic pH is also a chemical barrier on skin, in gut and reproductive tract
Source
source: Bozeman Science