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Difference Between Antigen and Pathogen

Antigen-and-Pathogen

Are you familiar with the terms antigen and pathogen? As we are currently dealing with this severe pandemic disease, corona, you must have heard about these specific terms! Today we come up to elaborate you the differences between antigen and pathogen. It might seem a little subtle to grab the distinction between the two, but we’ll try our best to provide a complete understanding.

A pathogen is any microorganism that is the cause behind sickness or disease. It includes all harmful bacteria, numerous viruses, many fungi, and protozoa. While on the counter side, an antigen is a describing characteristic of a pathogen. It is actually a molecule composed of complex carbohydrates and proteins that are further detected as a foreign particle by a body’s immune system. Manifesting it with a familiar example! For instance, a person suffering from Tuberculosis is attacked by the whooping cough bacterium, which has significant antigens on it.

We’ll look into the differences between antigen and pathogen in detail, but let’s first check out the comparison table below!

Comparison Table

Basis of ComparisonAntigenPathogen
ArrangementArranged as a moleculeArranged as an entire microorganism
SpecificityVery specificNo specificity
EffectDefining characteristic of a pathogenAttacks the host cell and produce destructive effects
TypesExogenous antigen, endogenous antigen, and autoantigenBacteria, fungi, viruses, and protozoa
CompositionMostly proteins or polysaccharidesIncludes all the essential composition as for a living micro-entity

Describe an Antigen

The antigen is a unique structure present on the surface of a pathogen. We can’t call it an organism but a molecule that is the fundamental reason behind initiating an antibody immune response. It defines the character of a foreign particle that is most of the time harmful to our body. As a result, the body activates itself and produces antibodies in defense. The foreign particles can be either bacteria, or viruses, or certain fungi.

Antigens are broadly classified as:

1.      Exogenous antigens

2.      Endogenous antigens

3.      Autoantigens

All those antigens attached at the surface of any pathogen/microorganism are known as exogenous antigens. On the other side, when antigens are produced inside a body due to some metabolic reactions, they are referred to as endogenous antigens. Last but not the least, autoantigens are the complex proteins in a body that is, unfortunately, recognized as foreign particles. Thus, they stimulate the immune response. All this mechanism ultimately causes self-destruction of a body, leading to different autoimmune diseases. One such example is ulcerative colitis.

Describe a Pathogen

These are all those microorganisms that can harm a body and induce diseases. Almost all pathogenic organisms have a particular origin with unique structures to attack a body. Different pathogens include protozoa, destructive bacteria, deadly fungi, and many viruses. Although viruses come under non-living bodies, their transferable viral part is so strong that it can even kill a person. We are all familiar with one such disease that has prevailed these days, coronavirus!

Pathogens are interlinked with antigens. These molecular structures are present on microorganisms to initiate their induction process, and as soon as they enter a body, their immunity activates! In other words, these structures help a body detect this foreign particle, or pathogen, and prepare itself for a fight. Sometimes the body wins the race and kills a pathogen, and sometimes the case is entirely different!

Know the Similarities Between Antigen & Pathogen

Apart from being distinct, there appears a few similarities between the two. Let’s find them below!

·         Either it’s a pathogen or an antigen; both kicks start a body’s immune system to protect it.

·         Both of them are capable of inducing disease.

·         These are often called immunogens.

Find the Dissimilarities Between Antigen & Pathogen

General Definition

Antigen

An antigen is a substance or a molecule attached to a pathogen, mostly as a defining property.

Pathogen

It is a microorganism that can attack a host cell and causes diseases.

Different Types

Antigen

An antigen is broadly categorized into three groups based on its location and function. These are exogenous antigens, endogenous antigens, and autoantigens.

Pathogen

While in contrast, pathogens can be viruses, bacteria, fungi, or protozoa.

Composition

Antigen

These are entirely the polysaccharides, proteins, or complex proteins, making up a molecule.

Pathogen

A pathogen is a complete microorganism with all principle functions to reside.

Effect on the Host Cell

Antigen

An antigen is a substance that works to identify its relative pathogen to a host cell, ultimately triggering the immune system.

Pathogen

A pathogen spreads its diseases after attacking the host cell.

Specificity

Antigen

These are highly specific towards its relative pathogen. Antigens of one microorganism can never be similar to the ones of another.

Pathogen

These are not so specific and can enter any living organism to produce its harmful effects.

Conclusion

Every human body consists of a particular immune system that activates itself every time a foreign particle enters. Our body does the same when a pathogen invades! The article above might have cleared your conflicts about the two terms, so we hope the differences between antigen and pathogen are now understood. When a pathogen enters a body, the body detects it through the specific antigens and triggers its antibodies. In most cases, this antigen-antibody complex helps a body win against the harmful pathogen.

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