What is Innate Immunity? An Overview!

The idea of immunity in humans may seem simple. However, it can be more vast than it appears.

There are three different types of immunities in humans, and innate immunity is one.

As awareness of innate immunity is crucial, we are discussing it in detail in this blog. You will find innate immunity definition and innate immunity examples here.

So, buckle up and read on.

What is Innate Immunity?

Innate immunity definition: Innate immunity refers to the body’s defense mechanism that humans are born with. It protects us from antigens. The main role of innate immunity is to safeguard us from harmful materials that may enter our bodies and affect our health. Innate immunity makes the first line of defense in our immune system.

Types of Innate Immunity

The innate immunity in humans comprises the following four layers of defense:

• Anatomic (skin and mucous membrane)
• Physiologic (temperature, low pH and chemical mediators)
• Endocytic and phagocytic
• Inflammatory

In the following sections, let’s discuss these four layers of defense in brief.

Anatomic Layer

The anatomic layer is a part of the innate immunity mechanism. It includes the skin, gastrointestinal tract, respiratory airways & lungs, nasopharynx (mucous membrane), eyes, and blood-brain barrier.

The most common defense mechanisms that associate with the anatomic layer are as follows:

• Sweat
• Desquamation
• Flushing
• Organic acids
• Peristalsis
• Gastric and bile acids
• Digestive enzyme
• Thiocyanate
• Defensins
• Gut flora
• Mucociliary escalator
• Surfactant
• Defensins
• Mucus, saliva
• Lysozyme
• Endothelial cells (via passive diffusion/osmosis & active selection)
• P-glycoprotein (mechanism by which active transportation occurs)

Physiologic Layer

Physiologic barriers of innate immunity include:

• Acidity of the stomach
• Presence of lysozyme
• Sweat
• Nasal hair

These barriers perform their specific functions and help keep us safe from diseases.

Endocytic and Phagocytic Layers

The endocytic barriers of innate immunity refer to the binding of pathogen molecules receptors on phagocytes, along with the induction of actin polymerization.
This leads to material internalization forming a phagosome, and encouraging fusion with late endosomes and lysosomes to sort them for degradation.

Inflammatory Layer

Inflammation is an innate immune response that occurs when the body detects an infection or tissue injury.

Wrapping up

Innate immunity’s meaning is simple. It refers to the immunity that we are born with. Strengthening and maintaining it requires attention to general and overall well-being. In this blog, we discussed innate immunity in detail. Hopefully, this was helpful.