07. immunity

Individual contracts pathogen without medical intervention. This means that the humoral immune response is initiated, and the person eventually makes their own specific and free-floating antibodies and develops an immunological memory of this pathogen.

Baby receives specific complementary and free-floating antibodies from their mother by breast feeding or the placenta. This means that the baby has no immunological memory.

Person receives specific complementary and free-floating antibodies by medical intervention (e.g. antivenom). This means that the person has no immunological memory.

Individual contracts pathogen with medical intervention. This means that the humoral immune response is initiated, and the person eventually makes their own specific and free-floating antibodies and develops an immunological memory of this pathogen. e.g. vaccine

A vaccine is a solution containing a dead, weakened or attenuated form of the of the pathogen or antigen, or mRNA instructions to make an antigen.

Herd immunityis when a large portion of a community (normally more than 90%) becomes immune to a disease, making the spread of disease from person to person unlikely as there are less potential hosts.

A pathogen that is new to a human population.

An emerging pathogen. Indigenous Australians did NOT have natural active immunity to smallpox (unlike colonists).

A pathogen that reappears after being absent in a population for a significant period of time.

An endemic disease is always present within a specific geographic area or population group, but the number of people affected is limited / under control

A rapid rise in the level of incidence of a disease in a localised area, community or region e.g. within a country or certain population

A significant rise in the level of incidence of a disease globally over multiple countries or continents

• Proximity to animals/animal products/zoonosis • Climate/Environmental change • Viral antigenic shift • Increased exploration/travel • Increased biotechnology

New pathogens released (e.g. from melting of polar caps, soil erosion)

Sudden and significant mutations in the genes encoding for viral surface antigens due to different viral strains from different species combining in the same host. This leads to a new viral strain that is likely to infect a different species (i.e. emergence of new pathogen).

Small and gradual mutations in the genes encoding for viral surface antigens (too slow to be a cause of the emergence of a new pathogen)

Humans have reached unchartered areas and encountered new pathogens or isolated populations have been exposed to new pathogen where they have no immunity

Sometimes new technology can be responsible for the release or escape of a pathogen.

• Identify antigen on desired cell (e.g. cancer cell or autoimmune disease-causing B cell) • Vaccinate a mouse with the desired antigen so that the mouse will create specific and complimentary plasma cells to the antigen • Plasma cells are extracted • Fuse mouse plasma cells with an immortal cell line from a tumour to produce a hybridoma. • This hybridoma will synthesise large quantities of specific monoclonal antibodies that will be isolated for use. *Optional: 6. humanisation… Where mouse-derived antigen-binding regions (CDRs) are grafted onto a human antibody structure.

So, the antibodies are less recognised as foreign (90% human, 10% mouse), thus, less likely to trigger an unwanted immune response.

Monoclonal antibodies (mAb) are laboratory produced antibodies that can bind to specific and complementary antigens on a cell (i.e. a cancer cell or autoimmune disease-causing cell).

Allergens are antigens that the immune system recognises as non-self and initiates a strong immune response towards.

Allergies are inappropriate or exaggerated reactions of the immune system to unimportant stimuli, an allergen. This means that there is an excessive release of histamine by mast cells causing exaggerated inflammation and mucus production.

Sensitisation Degranulation