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Does our immunity live in the blood? Add to ...

Welcome to the famed Zurich clinic of Dr. C. Wisdom III, pioneer of the blood-replacement therapy known as Renewing Internal Plasma Organics For Fitness – or RIPOFF.

THE QUESTION

If you had all your blood replaced by transfusion, would you need to have all your vaccinations done again? asks Catherine McMenemy of Burlington, Ont.

THE ANSWER

“Once someone's immune system has learned how to fight a specific type of virus or other pathogen, it is unlikely to forget,” which is what makes vaccinations so effective, writes Jacob Pendergrast, an assistant professor in the department of laboratory medicine and pathobiology at the University of Toronto and associate medical director of at the University Health Network Blood Transfusion Service.

Where does this memory reside? “Much of it is in barrier sites,” he says, “like skin, or the mucosal surfaces of the respiratory airways or gastrointestinal tract. This is where invading organisms are usually first encountered.”

If the infection spreads beyond those sites, he writes, it will encounter neutralizing antibodies that are continuously secreted into the blood by cells residing in the bone marrow. “As a result, you won't lose your immunity if all your blood is replaced (say, during major surgery) because this is not where the memory of your immune system lives.”

When you receive a vaccine, Dr. Pendergrast says, your immune system “goes to school” on it within your lymph nodes, and about a week later the first “graduates” emerge into the bloodstream. “Some of these are plasma cells, the cells that make antibodies.” Plasma cells can live in your bone marrow for years, he tells us, but may have to compete for space with other plasma cells generated by later infectious exposures. “Luckily, the vaccination will have also produced memory cells, which circulate in and out of your lymph nodes and spleen and are there to generate a whole new population of plasma cells if the infection ever returns.”

For reasons that still aren't fully understood, he adds, some vaccines work better than others, but much of it has to do with how often the target of the vaccine mutates. “Thus, a new flu shot is needed every year, but a single shot of the smallpox vaccine can cover you for your entire life.”

THE QUESTION

Is there any difference between being named John H. Smith Jr. and John H. Smith II? Dale Leitch of Victoria wants to know.

THE ANSWER

The “Jr.” is added when the father and son have the identical name, writes Harold Chmara of Toronto. It was considered pretentious to use “II” in this instance, he says, “since it would appear that the father was starting a dynasty and expected there to be many more generations to follow.”

But if the son was being named after a grandfather or a relative of an earlier generation, then the use of “II” was acceptable.

HELP WANTED

What was the origin of the term “braves,” referring to native American men? Anne Hildebrandt of Vineland, Ont., wants to know.

Robert G. Wuetherick of Edmonton wonders how, in the past, water stored in towers for steam locomotives was kept from freezing in winter.

When a dog wags its tail, writes Jean Buydens of Victoria, is this a voluntary action, like us waving a hand, or an involuntary reaction, like blinking?

Why do our arms and legs sometimes twitch when we are falling asleep? asks Sandy Potter of Mill Bay, B.C.

Let's hear from you: If you have the answer to one of these questions (or a question of your own) send an e-mail to wisdom@globeandmail.com. Please include your location and a daytime phone number.

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