The immune system is a complex network of cells, tissues, and organs that work together to defend us against germs. It helps our bodies recognize these "invaders" and keep them out of our system and, if it can't, find and get rid of them.

What would happen if our immune system does not work well?

1. Allergy and asthma: immune responses to substances that are generally not harmful.

2. Immune deficiency diseases: disorders that occur when one or more of the components that make up the immune system are missing.

3. Autoimmune diseases: disorders that cause the immune system to mistakenly attack our own cells and organs.

Immune Response

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Complex process
Starts with the presence of an infectious agent (fungi, bacteria, virus, parasite)
The most important prevention is INNATE IMMUNITY.
- Innate immunity forms a barrier so that we do not suffer from the disease and is in constant operation since we are in contact with infectious agents on a daily basis.
If the innate immunity is not able to control the infectious process continues and ends in DISEASE
The infectious agent enters the body and the adaptive immune system begins its work ………. recovery process
Specific immunological memory develops
- Reinfection with the original infectious agent
- Avoid disease

Innate	Acquire/Adaptative
Does not improve with repeated infection/is always the same	Improves with repeated infection
Composed of soluble factors: lysozyme, complement proteins, acute phase proteins (C-reactive, INF)	Composed of soluble factors: antibodies
Cells: phagocytes, NK (natural killers)	Cells: Lymphocytes T and B

Innate Immunity

The first line of defense -> Protects against antigens
We are born with it
- Does not develop new cells or new components
Immediate response (fast)
Nonspecific -> Has no memory

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Acquire/Adaptative Immunity

Composed of cells and specialized systemic processes
Eliminates foreign elements or antigens
Build immune memory

Humoral	Cellular
Transference by serum	Not transfer by serum
Mediated by antibodies	Mediated by lymphocytes T and other cells

The serum does not have cells, it only has soluble substances.

Memory

T and B lymphocytes capable of recognizing an antigen from a bacterium and are selected to multiply
Some for defense and others are preserved with the information (immunological memory)
Cells that retain information are stored
- They slow down their metabolic process
- Slow replication avoiding mutation or a change in the recognition capacity of these cells

Acquire immunity is the principle for vaccination

Why is it so specific?

1 antibody ONLY BINDS to 1 epitope of 1 antigen from 1 bacterium

Each antibody binds multivalently depending on the type of immunoglobulin or antibody it is treating, and some have multiple binding sites.

	Active	Passive
Natural	Clinical, sub-clinical infection	Breast milk, placenta
Artificial	Vaccination: live, killed purified antigens	Serum and cells

Active and natural: the presence of infection causes the system to recognize it naturally and activate itself
Natural and passive: very important during gestation through the placenta and after birth through breast milk, the mother transmits substances and immune cells to the antigens that the mother has faced during her life, so the newborn that is just beginning the process of maturation and development of the immune system it receives these cells and substances that help protect itself initially.
Artificial and active: is the vaccination where live attenuated moo is inoculated and it is not capable of inducing an infectious process or dead or also purified antigens that allow the system to be activated in an activated way.
Artificial and passive: through inoculation of serum or cells, the most common forms are antitoxin serums where the subject is inoculated with a serum that has antibodies against a toxin, for example, Clostridium botulinum, which harms the individual, it is not the bacteria, but the toxin. of the bacteria, the serum controls the infectious process.