It was a television commercial that piqued the interest of a Texas Tech researcher into trying a new approach for vaccine delivery.
Harvinder Gill is the Whitacre Endowed Chairman of Science and Engineering and an associate professor in the department of chemical engineering in the Edward E. Whitacre Jr. College of Engineering. He worked with Noureddine Abidi, the Leidigh associate professor in the department of plant and soil science in Tech's College of Agricultural Sciences & Natural Resources, and the managing director of the Fiber & Biopolymer Research Institute.
Together, Gill and Abidi, along with graduate students Pedro Gonzalez-Cruz, Md Jasim Uddin and Shashwati Atwe, published a paper on a new method for cleaning out the insides of pollen grains so the non-allergenic shells can be used to carry medicines or vaccines into the human body.
Gill recounted watching a television commercial for an allergy medication that contained an image of a pollen grain.
"I had never seen pollens before," he said. "They looked just really cool to me."
Reading up on pollen, he started wondering about how to advance existing research that would empty out the "bad" stuff inside the pollen shells that makes some people sneeze, leaving the spiky, resilient shell for use in delivering medicines, or in this case, vaccines.
Pollen shells, Gill explained enthusiastically, are very robust. They can withstand the enzymes in the stomach and make it into the mucosal surfaces of the intestines, where the spiky pollens can imbed in the mucous and release a vaccine into the body.
Gill said there are benefits to edible vaccines over traditional vaccine delivery via a hypodermic needle.
"We can classify advantages into two categories: psychological and immunological," Gill said. "Psychologically, no one wants to get a shot. It's painful for small children and their parents who don't want to see them in pain, and it's traumatizing for people who are afraid of needles. An edible vaccine could eliminate the need for needles."
Most infections happen through the body's mucosal surfaces, such as the nose or the gastrointestinal surfaces, Gill said. If a vaccine is delivered through the mucosal layers, there is a strong chance that antibodies will be induced in those layers, which further helps the body fight off pathogens, possibly before there is even an infection. Conventional shots are less effective at inducing antibodies in the mucosal surfaces.
This could be particularly helpful in the fight against HIV. An edible vaccine can help the body to induce antibodies in mucosal surfaces, Gill said.
Asked why researchers can't just put a vaccine into chocolate if they want people to eat it, Gill explained that without the protection of the resilient pollen shell, the vaccine would never make it through the acids of the stomach. Also, he said, the pollen grains somehow stimulate the immune system, helping in the process of creating immunity with the vaccines.
The Tech study published in "ACS Biomaterials Science & Engineering" is specifically about how to clean pollens so they can be used for processes like oral vaccines. But Gill said researchers at Tech have also been using the clean pollens with vaccines on mice and found that they are effective.
It's possible that the pollens could be used as a nasal spray, Gill said, but he said the pollens end up being hard particles, and he worries that they could cause inflammation. The body's intestinal system is designed to eventually expel the pollens, and so he said he worries less about inflammation via an oral vaccine.