What are the Parts of the Immune System?

Many cells and organs work together to protect the body. White blood cells, also called leukocytes, play an important role in the immune system.

Some types of white blood cells, called phagocytes, chew up invading organisms. One type of phagocyte is the neutrophil, which fights bacteria.

Other types of white blood cells, called lymphocytes, help the body remember who the invaders are in order to destroy them.

The two kinds of lymphocytes are B lymphocytes and T lymphocytes. Lymphocytes start out in the bone marrow. They either stay there and mature into B cells or go to the thymus gland to mature into T cells.

B lymphocytes are like the body’s military intelligence system — they find their targets and send defenses to lock onto them.

T cells are like the body’s soldiers — they destroy the invaders that the intelligence system finds.

B lymphocytes are triggered to make antibodies, which stay in the body. These specialized proteins lock onto specific antigens. That way, if the immune system encounters that antigen again, the antibodies are ready to do their job. That’s why someone who gets sick with a disease, like chickenpox, usually won’t get sick with it again.

This is also how immunizations (vaccines) prevent some diseases.

Although antibodies can recognize an antigen and lock onto it, they can’t destroy it without help. That’s the job of the T cells. They destroy antigens tagged by antibodies or cells that are infected or somehow changed. (Some T cells are actually called “killer cells.”) T cells also help signal other cells (like phagocytes) to do their jobs.

Antibodies also can:

● neutralize toxins (poisonous or damaging substances) produced by different organisms, and

● activate a group of proteins called complement that are part of the immune system. (Complement helps kill bacteria, viruses, or infected cells.)

These specialized cells and parts of the immune system offer the body protection against disease. This protection is called immunity.

Humans have three types of immunity — innate, adaptive, and passive:

● Innate immunity: Everyone is born with innate (or natural) immunity, a type of general protection. For example, the skin and mucousa acts as a barrier to block germs from entering the body. And the immune system recognizes when certain invaders are foreign and could be dangerous. This is our first line of defense. When innate immunity is breached, inflammation brings macrophages to the invading organism and engulfs the invaders. Inflammation is a life-protective response.

● Adaptive immunity: Adaptive (or active) immunity develops throughout our lives. We develop adaptive immunity when we’re exposed to diseases or when we’re immunized against them with vaccines or previous exposures.

● Passive immunity: Passive immunity is “borrowed” from another source and lasts for a short time. For example, antibodies in a mother’s breast milk give a baby temporary immunity to diseases to which the mother has been exposed. Some antibodies can be passed from mom to baby through the placenta.

For the first 10 years of your child’s life, antigens (triggers) help develop the memory cells (antibodies) that have already seen the enemy and may respond quicker.

While many parents are alarmed when their children get a cold, this is actually a proper immune system response. The occasional presence of coughing, sneezing, and fever shows that your child’s T cells are working properly.

Potential Problems with the Immune System

Sometimes, the immune system does not work properly. Let’s go over some potential problems with the immune system.

Allergic Disorders: When the immune system overreacts to elements in the environment (e.g., dust, mold, and cigarette smoke), your child may experience swelling, sneezing, watery eyes, eczema, food sensitivities, asthma, and sometimes anaphylaxis. Generally, allergies are preventable and reversible.

Autoimmune Disorders: This is when the immune system attacks the body’s healthy tissues and organs. Causes could be leaky gut, poor stomach health, or genetics. Autoimmune disorders are also preventable and reversible.

Immunodeficiency: When part of the immune system is not working properly. It could be acquired, secondary, or congenital (primary) immunodeficiency. Sometimes, natural remedies can help. If there is frequent illness — especially sinus problems — or poor growth, blood tests and possibly the help of an immunologist are necessary.

Allergies, dietary factors, and stress can act as pathogens. If a situation stresses the system for too much and for too long, the immune system can’t respond adequately. This is how people can literally overwork themselves into illness.

Be Well!

– Dr. Gluzman, “Doctor Mom”