ViraCyte Science

Restoring Natural Immune Defenses

Humans are born with a remarkable immune system that provides protection from nearly every microbial infection that exists or could exist in the future. Virus-specific T cells (VSTs) are an important component of this natural defense system, providing protection against thousands of viruses that could potentially cause disease. However, pathogenic viruses can go unchecked when the body’s natural immune system is compromised, such as after hematopoietic stem cell transplantation (HSCT) or due to HIV infection. In fact, the reactivation of dormant viruses is a frequent complication faced by HSCT recipients since their T cells are either absent or entirely incapable of responding to pathogens. When infections are detected in immunocompromised patients, they are typically treated with antiviral medications. Unfortunately, without an active immune system, antiviral medications have limited effectiveness with many patients suffering life-threatening organ damage, and even death despite conventional treatment.

Additional Literature

Our Vision

“Restore the natural virus fighting capability of a patient’s immune system through revolutionary T cell therapy.”

ViraCyte's Approach

ViraCyte’s solution is based on decades of scientific discovery, which now enables us to restore patients’ natural immune defenses by administering VSTs that are stimulated to recognize and attack specific pathogenic viruses. In preliminary clinical trials, over 90% of patients who have failed conventional therapy respond favorably to our therapy, most with a complete elimination of the viral infection.


To treat patients with active infection, ViraCyte has developed the “ready to administer” Viralym series of products (Viralym-A, Viralym-B, Viralym-C, and Viralym-M). All Viralym products are initially obtained from highly screened donors, whose T cells are expanded, educated, frozen, and stored for use when needed. Our manufacturing processes do not alter the genetic make-up of the T cells, nor do they expose T cells to the actual viruses. Instead, we use natural immune stimulant proteins combined with non-harmful fragments of the virus, much like those that could be used for traditional immunization. ViraCyte’s proprietary manufacturing processes allow hundreds of patients to be treated from a single donation; and ViraCyte’s proprietary CytoMatch™ algorithm enables a small panel of donors to be able to treat approximately 95% of all HSCT patients who need Viralym products.


In contrast to “ready to administer” Viralym products to treat active viral infection, ViraCyte has also developed and begun evaluation of Prelym, which is a personalized product made from the patient’s specific HSCT donor. T cells are purified from the donor, and depending on the donor’s immune status, T cells are expanded and educated to attack and kill up to 5 different viruses. Prelym is designed to be given to high-risk HSCT patients before they have an active infection, and thereby prevent their occurrence altogether. Depending on the individual stem cell donor, Prelym has been shown to prevent infections with up to 5 of the most dangerous viruses, simultaneously.