The immune system is designed to closely monitor the body for signs of intruders that may cause infection. But what happens if it malfunctions? Overactive and underactive immune systems can both have negative effects on your health.

What do antibodies, mucus, and stomach acid have in common? They’re all parts of the immune system!

The immune system is a trained army of cells, tissues, and organs that work together to block, detect, and eliminate harmful insults to your body. It can protect you from invaders like bacteria, viruses, fungi, and parasites.

Innate and Adaptive

The immune system is often thought of as two separate platoons: the innate immune system and the adaptive immune system. Although these two platoons have different jobs and are made up of soldiers with different specialties, they work together to prevent infections.

Bacteria can cause many common illnesses, including strep throat and ear infections. If you’ve ever gone to the doctor for one of these infections, they likely prescribed an antibiotic—a medicine designed to fight bacteria. Because bacteria can also cause life-threatening infections, antibiotics have saved many lives. However, the widespread use of antibiotics has fueled a growing problem: antibiotic resistance.

Antibiotic-resistant bacteria can survive some or even all antibiotics. Other microorganisms, including fungi, can similarly become resistant to the medicines that are used to treat them. Infections from these microorganisms affect many people and are difficult to treat. According to the Centers for Disease Control and Prevention, in the U.S. alone, resistant bacteria and fungi infect 2.8 million people each year, and more than 35,000 die as a result.

You might know that tiny individual units called cells make up your body. But did you know some of your cells die every day as a part of their normal life cycle? These deaths are balanced by other cells splitting into two identical cells, a process called mitosis.

Claira Sohn credits her grandfather with sparking her interest in science. Although he never studied science at a 4-year university due to financial limitations, he took many community college classes and worked in chemistry labs developing products such as hair dyes and dissolvable stitches. “Every morning, my grandfather would take me to school, and we’d stop to get orange juice and a cookie and talk about science. When I was in elementary school, he bought me a book about quantum mechanics written for kids,” she says. “He inspired me to ask questions and encouraged me to go to college.”

Claira enrolled at Northern Arizona University in Flagstaff after graduating high school. She majored in biomedical sciences and planned to become a medical doctor until her microbiology professor talked to her about the possibility of a research career. “That was an epiphany for me, because while I knew that there was research going on in the world, I didn’t realize there could be a place for me there,” Claira says. During her junior year, she joined the lab of Naomi Lee, Ph.D., where she first experienced what it felt like to be a researcher.

The power of computer code has been a longtime fascination for Tomas Helikar, Ph.D., a professor of biochemistry at the University of Nebraska-Lincoln (UNL). In college, when he learned he could use that power to help researchers better understand biology and improve human health, Dr. Helikar knew he’d found his ideal career. Since then, he’s built a successful team of scientists studying the ways we can use mathematical models in biomedical research, such as creating a digital replica of the immune system that could predict how a patient will react to infectious microorganisms and other pathogenic insults.

A Career in Computational Biology

Dr. Helikar first became involved in computer science by learning how to build a website as a high school student. He was amazed to learn that simple lines of computer code could be converted into a functional website, and he felt empowered knowing that he had created a real product from his computer.

The average human brain is only about 3 pounds, but this complex organ punches well above its weight, acting as the control center for the whole body. Many of the brain’s intricacies still aren’t fully understood. To gain more insight into brain processes, scientists often peer into the brains of research organisms such as fruit flies and mice. These organisms have shed light on how our brains maintain circadian rhythms, how neuropsychiatric disorders develop, and more.

Here, we feature images and videos that NIGMS-supported researchers have created while investigating the secrets of the brain in research organisms. Visit our image and video gallery for more eye-catching scientific photos, illustrations, and videos.  

The earliest Andrew Santiago-Frangos, Ph.D., remembers being interested in science was when he was about 8 years old. He was home sick and became engrossed in a children’s book that explained how some bacteria and viruses cause illness. To this day, his curiosity about bacteria persists, and he’s making discoveries about CRISPR—a system that helps bacteria defend against viruses—as a postdoctoral researcher and NIGMS-funded Maximizing Opportunities for Scientific and Academic Independent Careers (MOSAIC) scholar at Montana State University (MSU) in Bozeman.

Becoming a Biologist

Although Dr. Santiago-Frangos wanted to become a scientist from a young age and always found biology interesting, by the time he was attending high school in his native country of Cyprus, he had developed a passion for physics and thought he’d pursue a career in that field. However, working at a biotechnology company for a summer changed his mind. “That experience made me want to dive into biology more deeply because I could see how it could be directly applied to human health. Physics can also be applied to human health, but, at least at that time, biology seemed to me like a more direct way to help humanity,” says Dr. Santiago-Frangos.