11 Biology - Acquired Immunity

Acquired Immunity

Needs to be primed before it can be fully effective

• two types of white blood cells

  • B-Lymphocytes

  • T-Lymphocytes

Antigens

Bacteria / bad cell

Antibodies (immunoglobulins)

Small things that bind onto antigens to neutralise it. - Produced by B-Lymphocytes

B-Lymphocytes

Produces specific antibodies for specific antigens. - antibodies can also be found on the surface of B-cells

Antibody Functions

Block parts of the pathogen needed to survive and stop it from being harmful.

Tags the pathogens to signal and tell Phagocytes / white blood cells to begin phagocytosis.

Produces antitoxins to neutralise the pathogen.

These do not destroy / kill.

Antigens

A molecule (usually a protein) found on the surface of pathogens or foreign substances that is recognized by the immune system and triggers an immune response.

Clonal Expansion Definition (to do with B-Lymphocytes)

The cloning and differentiation of a specific B or T-Lymphocyte based on an identification of a specific antigen to produce specific antibodies

T-Lymphocytes

Membrane bound that recognise antigens on the surface of a pathogen

Clonal Expansion

Clones from Clonal Expansion differentiate to form either plasma cells or memory B-Lymphocytes.

Plasma Cells

Produce a large amount of antibodies that will float around the bloodstream.

Memory B-Cell

Same as B-Cells that last a long time that remembers how to react against the antigens / pathogens.

Process of Clonal Expansion

Once antibodies have been specified for a specific antigen, B-cells clone themselves and reproduce to then differentiate into either Plasma cells or memory B-cells.

Humoral Immunity

Involves B-Lymphocytes and is particularly good for pathogens outside of the bloodstream. Involves process of B-cells replication and differentiation and production of antibodies

Cell Mediated Immunity

Involves T-Lymphocytes which is stimulated by antigens themselves, attracting phagocytes, killing pathogenic cells, and activating monocytes which also attracts phagocytes. These attack infected cells

Types of T-Cells

• Cytotoxic T-Cells

• Help T-Cells

• Memory T-Cells

• Regulatory T-Cells

Cytotoxic T-Cells

Help destroy infected cells by punching holes in their cell membrane

Helper T-Cells

Send signals to other cells in the immune system on how to attack invaders, signalling cytotoxic T-cells, B-Cells, and other leukocytes.

Memory T-Cells

Quickly recognises and responds to pathogen that body has encountered previously which are specific to antigens that they were previously exposed to.

Regulatory T-Cells

Regulate immune response, preventing it from going into an overreaction and helps the immune system wind down after an infection has been depleted.

Natural Immunity

Immunity that happens naturally by itself

Natural Active Immunity

When the body is actively developing memory cells to resolve issues when exposed to pathogens.

Natural Passive Immunity

When a mother passes her antibodies to her foetus through the placenta. It is passive since the body did not create any memory cells.

Artificial Immunity

Injection of dead or somewhat alive antigen that forces the body to produce antibodies and memory cells.

Vaccines of Viruses

Since viruses evolve rapidly, vaccinations must be take every year to produce more

Artificial Passive Immunity - Serums

Antibodies that are being injected into the body that help fight and respond against antigens in the body. These are mostly used in emergency situations such as a venomous snake bite.

Autoimmune Diseases

When the body loses its ability to recognise ‘self’ from ‘non-self’ which can cause the immune system to attack its own cells, causing it to produce antibodies against certain of its own cells.