T Cells and B Cells Go to College

THE T cells and the B cells can’t just come out of the bone marrow and go off to war. Their weaponry is ultramodern. High-tech training is mandatory before they take to the field. The T cells will be involved in biological warfare. B cells will be specializing in guided missiles. They get their training for this in the technical colleges of the immune system.

Hence, half of the millions of lymphocytes produced every minute in the bone marrow go to the thymus gland​—a small gland located behind the breastbone—​for their training as T cells. Concerning this, the book The Body Victorious says: “The lymphocytes which attend the technical college of the thymus are the helper, suppressor, and killer cells called T-lymphocytes (or T-cells). They are among the most indispensable armed forces of the immune system.”

Antibodies​—10,000 per Cell per Second!

The other “half of the unschooled lymphocytes,” The Body Victorious tells us, are B cells that go to the lymph nodes and related tissues for their training to be able to manufacture and launch guided missiles, called antibodies. When the B cells “muster in these tissues, they are like blank pages: they know nothing, and must learn from scratch” to “acquire the capacity to react specifically against substances foreign to the body.” In the lymph nodes, a mature B cell, activated by helper T cells and related antigen, “proliferates and differentiates to form plasma cells that secrete identical antibodies with a single specificity at a rate of about 10,000 molecules per cell per second.”​—Immunology.

To help us absorb the magnitude of what the immune system is accomplishing, an article in the National Geographic, June 1986, details the problem confronting the thymus gland: “Somehow, as the T cells mature in the thymus, one learns to recognize the antigens of, say, the hepatitis virus, another to identify a strain of flu antigens, a third to detect rhinovirus 14 [a cold virus], and so on.” After commenting on the “staggering task the thymus confronts,” the article says that in nature there are “antigens in hundreds of millions of different shapes. The thymus must turn out a group of T cells that recognizes each one. . . . The thymus pumps out T cells by the tens of millions. Even though only a few of them may recognize any one antigen, the collective scouting force is vast enough to identify the almost infinite variety of antigens nature produces.”

While some of the helper T cells were stimulating the macrophages to multiply, others in the lymph nodes were coupling with the B cells located there, causing them to multiply. Many of them become plasma cells. Again, there must be the right receptors on the helper T cells to join up with the B cells and cause them to produce plasma cells. It is those plasma cells that start churning out thousands of antibodies a second.

Since each plasma cell makes only one kind of antibody, with a receptor specific for only one disease antigen, soon billions are on the front lines homing in on the antigens of one specific disease. They latch onto the invaders, slowing them down, causing them to clump together, making them more tempting morsels for the phagocytes to gobble up. This, together with the release of certain chemicals by the T cells, whips up the macrophages into a feeding frenzy, causing them to gobble up millions of the invading microorganisms.

Moreover, the antibodies themselves can lead to the death of these microorganisms. Once they have locked onto its surface antigens, special protein molecules, called complement factors, flock onto the germ. When the required number of complement factors are in place, they penetrate the membrane of the microorganism, liquid flows in, and the cell bursts and dies.

These antibodies, of course, must also have the right receptors to latch onto the intruders. On this point the 1989 Medical and Health Annual of the Encyclopædia Britannica, page 278, says that B cells are able “to produce between 100 million and a billion different antibodies.”

Killer T Cells Wage Biological Warfare

By now the helper T cells have recruited millions of the scavenger macrophages to gobble up the enemy and have stimulated B cells with their antibodies to join the fray against the invaders, but there are still other forces that the helper T cells call to battle. They marshal millions of the deadliest fighters to join the struggle​—the killer T cells.

The goal of viruses, bacteria, and parasites is to get inside the body cells because once there, they are safe from the macrophages and the B cells and their antibodies​—but not from the killer T cells! One of these infected cells needs only to brush against a killer T cell to cause it to shoot the infected cell full of holes with lethal proteins, destroy its DNA, and spill its contents out in death. In this way killer T cells can attack and destroy even mutant cells and cells that have turned cancerous.

In addition to killer T cells, there are other killer cells in the immune system’s weaponry, namely, natural killer cells. Unlike T and B cells, these natural killer cells do not need to be triggered by a specific antigen. Cancer cells and cells invaded by other viruses are vulnerable to their onslaughts. But their reach may not be limited to viruses. Scientific American, January 1988, says that their “main targets are thought to be tumor cells, and perhaps also cells infected by agents other than viruses.”

How do these disease fighters meet up with the invading microorganisms? Is it just hit-or-miss? No. Nothing is left to chance. Disease antigens and T cells, B cells, phagocytes, and antibodies circulate throughout the body by means of the bloodstream and the lymphatic system. The secondary lymphoid organs, such as lymph nodes, spleen, tonsils, adenoids, patches of specialized tissue on the small intestine, and appendix, are sites where immune responses are initiated. The lymph nodes play a major role. Lymph is the fluid that bathes the cells in our tissues. It originates in those tissues, collects in thin-walled vessels and flows to the lymph nodes, continues throughout the rest of the lymphatic system, and finally completes its circulation by emptying into the large veins that lead into the heart.

As the disease antigens pass through the lymph nodes, they are filtered out and trapped. The disease fighters of the immune system take 24 hours to complete the entire lymphatic circuit, but 6 hours of that time is spent in the lymph nodes. There they meet the trapped invading antigens, and major battles begin. Likewise, enemy antigens traveling in the bloodstream do not escape. They are channeled to the spleen, where disease fighters are waiting to confront them.

Now the war within us is over. The invasion forces are defeated. The immune system with its trillion or more white blood cells has won. It’s time for another category of T cells to take over, namely, the suppressor T cells. When they see that the war has been won, they call off the battle and close down the fighting forces of the immune system.

Memory Cells and Immunity, With Complications

By this time, however, the B cells and the T cells have performed another vital service: They have produced memory cells that circulate in the bloodstream and the lymph vessels for many years​—in some cases for a lifetime. Should you ever be infected with the same strain of flu virus or cold virus, or with any other foreign substance encountered in the past, these memory cells will spot it immediately and rally the immune system for a quick and overwhelming assault. The memory cells will swiftly produce a flood of the specific type of B cells and T cells that fought off the first attack of this particular assailant. This new invasion is stamped out before it gains a foothold. What originally might have taken three weeks to defeat is now whipped before it gets started. Your previous infection by that particular invader has left you immune to it.

The picture is complicated, however, by the existence of different strains of flu viruses, often originating in different parts of the world. In addition, there are some 200 strains of cold virus, and each strain has its own particular antigen. So there must be 200 different types of helper T cells, each type having a receptor that matches the antigen of one of the 200 cold viruses. But that’s not all. The cold and flu viruses are constantly mutating, and each time that happens, there is a new cold or flu antigen that requires a new helper T-cell receptor to fit it. The cold virus keeps changing the locks, so the T cell must keep changing the keys.

Before you poke fun at doctors who can’t cure the common cold, understand the problem. The particular cold you have may be cured and never attack you again, but a newly mutated cold virus comes along, and your immune system must come up with an entirely new helper T cell to rally the immune forces to fight it. Win one battle, soon another begins. The war is endless.

Brain and Immune System Communicate

No wonder the immune system has been compared favorably with the brain. Research continues to show that it and the brain talk to each other about our health and that the mind exercises influence over the body, including the immune system. The following quotes indicate a relationship between brain and immune system. It’s a case of mind over body and body over mind.

“Immunologists are discovering more about the links between mind and body, the mechanisms of psychosomatic disease.”​—National Geographic, June 1986, page 733.

Recognized but little understood is the connection between the immune system and the brain. Mental stress, bereavement, loneliness, and depression affect the workings of the white blood cells, or lymphocytes, and this reduces T-cell activity. “The biological basis of these interconnections remains much of a mystery. It is clear, however, that the nervous and immune systems are inextricably linked, anatomically and chemically.”​—The Incredible Machine, pages 217, 219.

“The immune system . . . rivals the central nervous system in sensitivity, specificity, and complexity.”​—Immunology, page 283.

Science magazine reported on the link between the brain and the immune system: “A great deal of evidence shows that the two systems are inextricably interconnected. . . . The emerging picture shows that the immune and nervous systems are highly integrated, able to talk back and forth to coordinate their activities.”​—March 8, 1985, pages 1190-1192.

All of this reflects the infinite wisdom of the Creator of both the immune system and the brain. And this, in turn, makes us question whether our Creator, after building into us such amazing wonders as the brain and the immune system, would then program us to die. Actually, he did not do so; it is the scientist that says we are made thus. We are told that cells divide​—more than 200 million are created in our bodies every minute—​to replace injured and worn-out cells. But our cells, the scientists say, will divide no more than 50 times. Soon we are losing more than we are replacing, old age sets in, and death follows.

But this is not the way man was created; man brought this on himself. He was created to live, be fruitful, become many, fill the earth, and take care of the earth​—as long as he was obedient to his Creator. But he was warned: Disobey, and “dying you will die.” The first man disobeyed, had guilt feelings, and hid himself. From that moment on, humanity has been in the process of dying.​—Genesis 1:26-28; 2:15-17, Reference Bible, footnote; Ge 3:8-10.

In time, strong negative feelings become a “rottenness to the bones,” and “a spirit that is stricken makes the bones dry.” The result is an immune system of diminished capacity, since healthy, moist bone marrow is needed to produce an abundance of the disease-fighting white blood cells.​—Proverbs 14:30; 17:22.

But the process of dying will be replaced by one of living, and a perfectly functioning immune system will be an important factor in contributing to that. Jehovah’s purpose to have a paradise earth filled with righteous, obedient humanity will be accomplished through the ransom sacrifice of Christ Jesus. Then no one will be sick, death will be destroyed, and all flesh will “become fresher than in youth.” (Job 33:25; Isaiah 33:24; Matthew 20:28; John 17:3; Revelation 21:4) Then the amazing immune system designed by Jehovah will never lose a battle with any invading agents.

Even now, our immune system, with its shortcomings, is a miracle of creation. The more we learn about it, the more we stand in awe of its Grand Creator, Jehovah God. We join the psalmist David in his inspired expression: “I shall laud you because in a fear-inspiring way I am wonderfully made. Your works are wonderful, as my soul is very well aware.”​—Psalm 139:14.

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Defenders in the Ranks of the Immune System

1. Phagocytes Feeding cells, of two kinds: neutrophils and macrophages. Both are scavengers that consume inanimate trash, dead cells and other rubbish, and large numbers of invading microbes. Macrophages are bigger, tougher, stronger than the neutrophils, living longer and ingesting many more microorganisms. Much more than garbage disposal units, they manufacture different enzymes and antimicrobial agents, and they function as communication links between other cells of the immune system and even the brain.

2. MHC (major histocompatibility complex) Molecules on the surfaces of cells that identify the cells as a part of the body. On macrophages, the MHC displays a bit of the antigens of victims the macrophage has ingested, which stimulates both helper T cell and macrophage to multiply prodigiously to increase their ranks to battle with infection.

3. Helper T cells They are chiefs of operations of the immune system, identifying enemies and stimulating the production of other warriors of the immune system, rallying them to join battle with the invaders. They call up reinforcements in the ranks of macrophages, other T cells and B cells, and stimulate the production of plasma cells.

4. Lymphokines Hormonelike proteins, including interleukins and gamma interferon, by which immune cells communicate with one another. They activate many vital reactions of the immune system, thereby boosting its response to disease germs.

5. Killer T cells These T cells destroy cells in which viruses and microbes have hidden. They fire lethal proteins into these cells, punching holes in their membranes and causing the cells to rupture. They also eliminate cells that have turned cancerous.

6. B cells Under the stimulus of helper T cells, B cells increase in numbers, and some divide and mature into plasma cells.

7. Plasma cells These cells produce antibodies by the millions, which, like guided missiles, then circulate throughout the body.

8. Antibodies When antibodies come across antigens their receptors can latch onto, they grab them, slow them down, cause them to clump together to become tempting morsels for the phagocytes to gobble up. Or they do the job themselves, with the help of the complement factors.

9. Complement proteins Once the antibodies have locked onto the surface of the microorganism, proteins called complement flock onto it and inject liquid into it, causing it to burst and die.

10. Suppressor T cell When the infection is contained and the immune system has won, the suppressor T cells go into action and use chemical signals to halt the entire range of immune responses. The battle is won.

11. Memory cells By this time the T cells and the B cells have produced and left behind memory cells that circulate in the bloodstream and lymphatic system for years, even a lifetime. If another invasion is mounted by the same kind of organism that was previously defeated, an overwhelming attack is mounted by these memory cells, and this new invasion is quickly crushed. The body is now immune to that particular microorganism. This is the mechanism that makes vaccinations effective in eliminating diseases that were once scourges​—measles, smallpox, typhoid, diphtheria, and others.

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An Explosive Increase in Knowledge, but the Mystery Remains

Since the AIDS virus struck and zeroed in on the immune system for a knockout, research has shot into high gear. Knowledge has increased tremendously. Nevertheless, the immune system is so amazingly complex that much about it remains a mystery, as the following quotes from immunologists show.

Immunologist John Kappler says: “The field is progressing so rapidly that the journals are out of date by the time they are published.”​—Time, May 23, 1988, page 56.

Immunologist Leroy Hood, of the California Institute of Technology, says: “We’ve gained a good understanding of the hardware of the immune system, but we know almost nothing yet about the software that runs the system​—the genes that tell our cells what to do.” Concerning the hormonelike chemical signals that trigger reactions, the lymphokines, Hood says that the ones discovered so far are “just the tip of the iceberg.”​—National Geographic, June 1986, page 732; Time, May 23, 1988, page 64.

Researcher Edward Bradley: “We probably know as little about the immune system now as Columbus knew about the Americas after his first voyage.”​—National Geographic, June 1986, page 732.

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Marijuana smoking “plays a crucial role in weakening the immune system by limiting the development of certain white blood cells.”​—Industrial Chemist, November 1987, page 14.

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When the War Becomes a Civil War

“The ability to discriminate between self and nonself is a hallmark of the immune system.” (Immunology, page 368) But when the system goes awry​—as it sometimes does—​it fails to discriminate between self and nonself and ends up in civil war, fighting itself. The maladies that then afflict us are called autoimmune diseases. Thought to be among them are rheumatic fever, rheumatoid arthritis, multiple sclerosis, Type 1 diabetes, myasthenia gravis, and systemic lupus erythematosus.

Additionally, the immune system sometimes errs when it views harmless intruders as dangerous enemies. It may be a grain of pollen, a particle of dust, animal dander, or a bit of crab that causes an allergic reaction. Excessive quantities of potent chemicals, such as histamines, are produced to fight off items that are harmless in themselves. The symptoms of these allergic reactions can be very distressing​—wheezing, sneezing, sniffles, runny nose, watery eyes. If extreme, these reactions can lead to a shocklike state called anaphylaxis and can even cause death.

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The evidence mounts that blood transfusions are harmful to the immune system. Hundreds of scientific papers over the past several years have linked blood transfusions to immune suppression. “One unit of whole blood was sufficient to see immunosuppression,” one report said.​—Medical World News, December 11, 1989, page 28.