Researchers have found a new way to quickly and ethically test potential vaccines without relying on animal trials.
Traditionally, developing and testing new treatments or vaccines requires extensive animal experimentation, which can take years and raise ethical concerns about animal welfare.
However, by using lab-grown mini-organs, scientists have discovered a more efficient and humane way to test vaccine candidates.
In a recent study published in ACS Central Science, researchers have introduced a novel testing platform that encloses B cells, crucial components of the immune system, within miniature “organoids.”
This innovative approach accelerates the vaccine screening process while minimizing the number of animals required for testing purposes.
The function of vaccines is to expose the immune system to an antigen, which could be a portion or the entirety of a virus or bacterium. This, in turn, enables the body to prime itself for future exposure by instructing its B cells to produce antibodies against the antigen.
Some bacteria cloak themselves in a polysaccharide “disguise,” which necessitates the use of specialized conjugate vaccines, including those that safeguard against pneumonia and meningitis. In such cases, a fragment of the antigenic polysaccharide is attached, or conjugated, to a carrier protein that the body can recognize. However, the mechanism by which conjugate vaccines interact with B cells to elicit an immune response remains incompletely understood.
The conventional method of testing vaccines entails injecting them into animals and waiting for several weeks or even months to observe the outcome. However, when developing a completely new type of vaccine or focusing on a new target, researchers usually need to assess multiple vaccine candidates, necessitating a considerable number of animal studies.
In an attempt to expedite the vaccine development process and address ethical concerns associated with animal testing, scientists are investigating the use of organoids. These miniature cell clusters imitate organs and generate a simulated environment that closely resembles in vivo conditions.
The spleen of a single animal can generate hundreds of immune cell organoids, significantly enhancing testing capacity. This, in turn, may assist scientists in keeping up with the extensive array of compounds they can develop and must screen.
Matthew DeLisa, Ankur Singh, and their team aimed to determine whether this approach would yield outcomes similar to those observed in animal trials and whether the platform could be utilized to evaluate numerous glycoconjugate vaccine candidates.
To generate organoids, they separated B cells from the spleens of mice, introduced cellular signaling molecules and structural components, and then enclosed the mixture within a synthetic hydrogel matrix.
The team subsequently produced conjugate vaccine candidates aimed at combating the bacterium that triggers tularemia, also known as “rabbit fever,” for which there is no authorized vaccine at present. The candidates were tested using both traditional in vivo mouse experiments and the new organoid platform.
In both experimental formats, the B cells exhibited comparable reactions and offered valuable insights into the biochemical modifications that arise as the cells mature and produce antibodies.
Consequently, the researchers discovered that the platform can identify B cell clones that produce exceptionally antigen-specific antibodies, which have diverse potential applications.
While this study’s findings are preliminary, they anticipate that the organoid platform could potentially shorten the duration required for the development and evaluation of new conjugate vaccines.
Source: 10.1021/acscentsci.2c01473
Image Credit: shutterstock
