Tag Archives: antigens

STD Awareness: Searching for an HIV Vaccine

Posted on by

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 →

Over 90 Percent of What Planned Parenthood Does, Part 6: Vaccinations

Posted on by

Welcome to the latest installment of “Over 90 Percent of What Planned Parenthood Does,” a series on Planned Parenthood Advocates of Arizona’s blog that highlights Planned Parenthood’s diverse array of services — the ones Jon Kyl doesn’t know about.

You know what they say: An ounce of prevention is worth a pound of cure. Public health experts agree that vaccines are one of the most important advancements in medicine, and are incredibly safe and effective in preventing infectious disease. Many infectious diseases that used to lay waste to their victims are now unknown to many of us in the developed world — polio, whooping cough, measles, and rabies struck fear in the hearts of our forebears, but most young people today barely know what they are (although low rates of vaccination can still lead to outbreaks, such as 2008’s measles outbreak in Tucson). Smallpox, once a terrifying scourge, has been wiped off the planet thanks to vaccination campaigns.

We offer vaccinations against hepatitis A and B, as well as HPV.

Vaccines work by introducing antigens to your immune system. An antigen is a substance, such as a protein on the surface of a virus, that the immune system can recognize as dangerous. It is then able to attack the pathogen and, often, create a “memory” of that pathogen so it can attack it in the event of reinfection. The antigens in vaccines are very safe, and can be derived from many sources, such as inactivated (dead) or attenuated (weakened) pathogens, or fragments of pathogens. Some vaccines, such as those protecting against human papillomavirus and hepatitis B, are made with laboratory-synthesized fragments of the surface proteins of viruses, which are sufficient to produce immune response despite being completely noninfectious.

Planned Parenthood Arizona offers vaccinations against hepatitis A, hepatitis B, and human papillomavirus (HPV). All three of these viruses can be transmitted sexually, and hepatitis B and HPV can cause cancer if the infections become chronic. The hepatitis vaccines have led to all-time lows in rates of hepatitis A and hepatitis B; the HPV vaccine is still new, but emerging evidence suggests a possible decrease in HPV rates as herd immunity grows. Vaccination doesn’t just benefit you and your partner(s) — it benefits society as a whole. Continue reading →

World Hepatitis Day: The History of the Hepatitis B Vaccine

Posted on by

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 →