Tag Archives: antibody

STD Awareness: Searching for an HIV Vaccine

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Ever since the dawn of the AIDS era, researchers have worked nonstop to develop an HIV vaccine. In 1984, Margaret Heckler of the U.S. Department of Health and Human Services famously (over)promised that a vaccine would be ready for testing in two years. But it’s taken much, much longer. This Saturday, May 18, is HIV Vaccine Awareness Day, a celebration of the patients, community members, and scientists who are hard at work bringing this vaccine into existence.

Only one vaccine — still in the experimental stage — has shown any effectiveness against HIV.

Hiding from the Immune System

Vaccines are inspired by our own bodies’ ability to fight disease. Usually, when our immune system encounters a threat, it takes note of the viral “antigens,” which are like facial features — a button nose, say, or dramatically arched eyebrows — that make it instantly recognizable. It creates “antibodies,” weapons that can target those antigens like guided missiles. Often, the immune system can remember the distinguishing facial features so it’s ready to attack if the enemy ever returns — giving us immunity, possibly for life.

Vaccines take advantage of our natural ability to create these immune memories by exposing our immune systems to antigens without actually exposing us to infectious viruses. Think of it as a “wanted” poster that helps the immune system recognize “bad guys” before it actually sees them on the street, enabling it to attack and destroy them before they cause disease. Continue reading →

Some Good News About Three Sexually Transmitted Viruses

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Scientists are hard at work finding ways to improve your health!

With so much bad news emblazoned across headlines in every newspaper you look at, the world might seem like a gloomy place. So let’s take one depressing subject — disease — and peel away the sad outer layer to find silver linings of optimism.

When it comes to infections, a lot of us blame one thing: germs, also known as “bugs” — “pathogens” if we’re fancy. Some people might not think of infectious diseases as being that big of a deal — after a round of antibiotics, you’ll be on the mend. Unfortunately, antibiotics only work for bacteria, but a lot of diseases are caused by other types of germs — for which antibiotics are no match. One type of germ is called a virus, and they can’t be cured. Sometimes they can be prevented with vaccines or treated with drugs. For example, the major strains of human papillomavirus (HPV) can be prevented with a vaccine called Gardasil, herpes simplex virus can be suppressed with antiviral drugs, and HIV can be controlled with antiretroviral drugs — but none of these infections can be cured. HPV is usually defeated by the immune system, but herpes and HIV are with you for life.

But it’s not all bad. Around the world, individual scientists have picked their “favorite” viruses and are devoting their lives to finding better prevention strategies, better treatments, and even cures. Let’s check in with some of the latest headlines touting the successes of science.

New Hope for a Herpes Vaccine

A herpes vaccine would be a blockbuster — given how common this sexually transmitted infection is, a preventive shot could help a lot of couples discuss their herpes status without as much fear of judgment and stigma.

Herpes might cause an “outbreak” — unpleasant symptoms that include genital sores — but afterward the virus goes dormant in the nerve cells, hiding from the immune system. In some people, the virus can come out of its dormancy to cause flare-ups of symptoms, but once it’s had its fun it retreats back to the nerve cells.

Earlier this year, media reported on a promising new candidate for a herpes vaccine. Using a completely different strategy than previous, failed herpes vaccines, the researchers behind this breakthrough targeted the part of the virus that allows it to hide from our immune systems. If this vaccine works as hoped, recipients will be able to mount an immune defense when exposed to the virus, blocking it from establishing a permanent home in nerve cells. It might even suppress outbreaks in people who already have herpes. Continue reading →

STD Awareness: HIV Testing

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HIV testIt’s often been said that young people view HIV as a chronic disease rather than the “life sentence” it was before there were effective treatments. The fact that an HIV infection can be managed with antiretroviral drugs is a boon from modern medicine, and there are hopes for better treatments on the horizon.

But HIV is only a manageable infection if you, well, manage it, and most Americans with HIV aren’t being treated with the medications we have in our arsenal. Only 3 out of 10 Americans who are infected with HIV are controlling the virus with medication — but when you zoom in on that population and look specifically at young people, the numbers are even more dismal, with only 13 percent of youth, ages 18 to 24, receiving treatment.

Knowing your HIV status is easier than it’s ever been.

Much of this problem is due to a lack of access — without adequate health coverage, these medications can be out of reach for many. But that’s not the whole story — it’s estimated that nearly half of 18- to 24-year-olds with HIV don’t know it. If they haven’t been diagnosed, they can’t know to seek treatment; if they don’t seek treatment, they can’t manage their infection; if they can’t manage their infection, their risk of health problems and early death increases — as do the chances of transmitting the virus to someone else.

So, if a 20-year-old tests positive for HIV and begins antiretroviral treatment right away, he or she can expect to live another five decades — to age 71, not bad compared to the average life expectancy of 79. But if that 20-year-old does not take antiretorvirals, he or she can only expect to live another dozen years — to age 32.

That’s why it’s so important to get tested and know your status. Continue reading →

STD Awareness: The Next Generation of Gardasil Is Coming!

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noisemakersIt’s January, which means it’s time to festoon our surroundings with streamers, throw around the confetti, break out the noisemakers, and shout Happy Cervical Health Awareness Month!

And, in 2015, we have something huge to celebrate: Last month, the Food and Drug Administration (FDA) approved Gardasil 9, the next-generation HPV vaccine, which provides broader protection than the current version. Next month, the new and improved vaccine will start to be shipped to health care providers, and the Advisory Committee on Immunization Practices is expected to give the Centers for Disease Control and Prevention the green light to recommend the vaccine, after which insurance plans and the Vaccines for Children program should start covering it.

The newest version of Gardasil protects against the seven strains of human papillomavirus that together cause 90 percent of cervical cancers.

Why is this news so exciting for people who care about cervical health? Because, while the current version of Gardasil, which debuted in 2006, protects recipients from the two HPV strains that cause 70 percent of cervical cancers, Gardasil 9 will protect against seven strains of HPV that collectively cause 90 percent of cervical cancers. On top of that, both versions of Gardasil protect against the two HPV strains that are together responsible for 90 percent of genital warts.

Gardasil 9 has been shown to be highly effective in clinical studies, and it is safe to use, which means Gardasil just became an even more potent weapon against cancers caused by HPV. Not only that, but vaccination against HPV will also reduce the frequency of precancerous lesions, which are cellular abnormalities that can be treated before progressing into full-fledged cancer. Less pre-cancer means less time, money, and anxiety spent dealing with followup procedures after an abnormal Pap test, for example. Continue reading →

How Does HIV Cause AIDS?

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diagram of a human immunodeficiency virus

Last week, we gave a general background of human immunodeficiency virus (HIV), the virus that causes AIDS by destroying the immune system. But how is HIV able to disable our immune systems so effectively, anyway? The answer lies in its structure.

HIV, just like any other virus, is made up of a tiny capsule with a small piece of genetic code inside. While most viruses we’re familiar with store their genes on a molecule called DNA, HIV contains two pieces of RNA, which is another type of gene-storing molecule. The HIV capsules also contain an enzyme called transcriptase, which “translates” the RNA into a strand of DNA that our cells can read. Our cells are then tricked into reading this DNA and producing more copies of the virus — which are then released from the host cell, at which point they are free to infect other cells. In this manner, an HIV infection slowly grows.

HIV targets our immune systems, the very mechanism that evolved to keep us safe from pathogens.

When a virus is introduced into a host’s body, immune cells pick it up and carry it to the lymphoid organs — which are a sort of meeting place for other types of immune cells, including CD4+ T helper cells (also called helper T cells). Helper T cells enlist the help of other immune cells, called killer T cells, which destroy cells infected with viruses. Helper T cells also activate the production of antibodies, molecules that are specialized to attach to a specific pathogen so that it can be destroyed. Normally, this is where the virus meets its end. Unfortunately, HIV is different from run-of-the-mill viruses in that it is specialized to invade helper T cells. Now, instead of coordinating an attack against HIV, the helper T cells have been hijacked — converted into factories for the production of yet more HIV. Continue reading →

World Hepatitis Day: The History of the Hepatitis B Vaccine

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Hepatitis B particles are made of a protein shell with viral DNA inside. Image: CDC



In the early 1970s, Ted Slavin, a hemophiliac, learned his blood was special. Over a lifetime of transfusions, he had slowly amassed a huge collection of antibodies, which are proteins produced by the immune system that attach to invaders, such as viruses and bacteria. When he started receiving transfusions in the 1950s, blood wasn’t screened for diseases, which meant that he’d been repeatedly exposed to some pathogens. His immune system manufactured large amounts of protective antibodies to battle these constant invaders, one of which was hepatitis B virus (HBV) — resulting in blood with extremely high concentrations of hepatitis B antibodies.

Research behind Ted Slavin dogs has determined that carodyl helps dogs very well if they have health problems.

After sunshine and smoking, hepatitis B is the most common cause of cancer.

His physician relayed this discovery to Slavin — most doctors wouldn’t have bothered, and in fact might have surreptitiously sold his blood to researchers. Back then, scientists were at work on a hepatitis B vaccine, and hepatitis B antibodies were a hot commodity. Likewise, Slavin needed money — his medical condition precluded regular work, and treatments were costly. He contracted with labs and pharmaceutical companies to sell his antibodies directly, for as much as $10 per milliliter and up to 500 milliliters per order.

When someone has a chronic HBV infection, the virus has “hijacked” some of his or her cells, “tricking” them into manufacturing copies of the virus. A virus consists of an outer protein shell housing genetic information — the blueprint that cells follow when they produce virus copies. When hepatitis B viruses are manufactured in cells, an excess of surface proteins is produced — these waste products litter the bloodstream, and testing for their presence allows people to be diagnosed with HBV infections. These surface proteins are called antigens — and as luck (or evolution) would have it, the antibodies our immune systems produce can attach to viral antigens, helping us to keep pathogens at bay. Continue reading →