Innate Immunity:

Here the answer will always be the same regardless of the nature of the microorganism (virus, fungi, parasites), I mean, it is the ability to react widely against microorganisms or foreign substances.

This type of immunity is genetically determined, varies between species and even in individuals of the same species. This varies according to race, hormonal system, age and sex.

The main feature of this immunity is that it doesn't require prior contact with the antigen, I mean, it doesn't matter if it is the first time or not that it contacts a microorganism because the response will be the same. So whether the response is effective or not, all microorganisms regardless of their characteristics have something in common, and are called "Pathogen-associated molecular pattern" (PAMPs), through which our body can know that something strange is found, through the called "pattern recognition receptors" (PRRs)

Our body doesn't need to recognize the entire microorganism because they have lipopolysaccharides, peptidoglycan,lipoteichoic acid, bacterial DNA and glucan, which would be the equivalent to our organs and body parts and correspond to PAMPs.

Normal microbial flora:

Correspond to those microorganisms that are permanently in normal conditions in our skin, and they protect us from those external microorganisms that want to invade us. It consists of several mechanisms of action to defend ourselves such as for example modifying the pH of the place, or releasing peptides with antibiotic activity called colicins.

An example of the microbiota could be the Döderlein bacilli (Lactobacillus) found in the vagina which make the vaginal pH always acidic and therefore inhospitable for many external microorganisms.

• At the skin level, if it does'nt receive an injury that manages to undo its continuity, it is difficult for a person with an optimal immune status could enter a microorganism in his body. Also to the sweat glands that protect us through sweat (by dermicidin which is an antimicrobial peptide); The sebaceous glands also protect us by producing antimicrobial lipids for example.

• At the level of the airways are the turbinates, epiglottis, cough and sneeze mechanism (to expel whatever who wants to enter our body, they are the most important), the mucus (makes it difficult for the microorganism to enter), lysozyme (enzyme with bactericidal property found in tears, saliva, breast milk), lactoferrin (a protein with a lot of iron affinity, which acts as an antimicrobial and is found for example in the blood, semen, saliva) and other polysaccharides.

• At the level of the digestive system, a mucus is also found in the stomach that prevents invaders from attaching, and the same acidic pH of that site eliminates most microorganisms. In the small and large intestine there are millions of microorganisms (mostly anaerobes) that eliminate those that are pathogenic.

• At the level of the urinary tract, the mechanism of urine ejection, the exit force of the urine prevents microorganisms from inhabiting, because said ejection works as a drag mechanism. The pH of the urine produces a hostile environment; Tamm Horsfall proteins prevent the adherence of microorganisms, and the narrow urethral sphincter prevents their entry.

• At the genital level, in man the seminal fluid has bactericidal action, and the pH is alkaline; In women as I mentioned above are the Döderlein bacilli that maintain the acidic pH in the vagina.

Mechanisms of innate immunity:

• Physical barriers.

• Inflammatory mechanism.

• Humoral mechanism: alternate pathway of the complement system.

• Cellular mechanism: phagocytosis and activation of natural killer cells.

Inflammatory mechanism:

Basically it is a mechanism whose main function is to save time for the cells responsible for destroying the pathogenic microorganism to arrive, this is achieved by “corralizing” it so that it does not expand further. This mechanism is activated when the tissues are injured, it is a quick response because the cells and substances that cause inflammation reach through the circulatory system.

So what is the purpose of inflammation?

Cordoning the microorganism so that it doesn't expand further, that is why this mechanism is very important.

Acquired Immunity:

This one is perfected over the years as we are exposed to different types of microorganisms, this type of adaptation can be acquired whether or not suffering from diseases.

This type of immunity keeps a specific memory for any pathogen, that is, your response will vary depending on the microorganism you are going to face, so a person who was exposed to an antigen, his body will produce specific antibodies for that antigen not to another, for example: if I had rubella, it doesn't mean I can't give me measles because my body is prepared for rubella, not for measles.

Antigen: it is a harmful foreign entity, but it can also be a part or some structure of that pathogenic microorganism, which upon entering our body produces an immunological response and therefore the production of antibodies.

Antibody: they are glycoproteins whose function is to identify and specifically combat the antigens that invade our body.

The defense mechanisms of acquired immunity are composed of 2 parts, the cellular part that are T and B lymphocytes; and the molecular part that are the antibodies or immunoglobulins.

Acquired immunity uses 2 types of immunity: Active immunity and passive Immunity.

Active immunity: It is one that is produced by previous contact with a microorganism, whether we have suffered an infectious process or not. This is further subdivided into:

-Natural active immunity: when we suffer the disease.

-Active artificial immunity: through vaccines which are injections containing antigens of a particular microorganism.