This composition of disparate compounds achieves a powerful immunostimulant, boosting the efficacy of a wide variety of vaccines. Vaccines are an invaluable public health measure, crucial for fighting pandemics, child mortality, and cancer. Estimates suggest childhood vaccinations have saved over 100 million lives in the last 50 years. Vaccines are also emerging as weapons against cancer thanks to their ability to stimulate the immune system to attack tumors. The core of a vaccine is the antigen, a derivative of an infectious agent the immune system learns to recognize. However, the vaccine or antigen alone typically does not attract enough attention from the immune system to create a lasting immune response or memory. To overcome this problem, adjuvants, compounds that boost vaccines to induce a strong immune response, are widely applied alongside vaccines to achieve lasting immune memory. But the utility of each adjuvant is often specific to a single vaccine.
Researchers at the University of Florida have developed a new type of vaccine adjuvants by covalently bonding two distinct immunostimulant compounds, monophosphoryl lipid A (MPLA) and either 2,4-dinitrophenyl (DNP) or rhamnose that triggers two different immune response pathways. The concerted effect of these two immunostimulants promises the conjugate adjuvants with robust efficacy and broad applicability to boost vaccines that prevent viral and bacterial infections and treat cancer.
Activates a strong immune response a vaccine to create immune memory to infectious diseases or initiate an immune attack against cancerous cells
Compounds that help vaccines provoke immune responses in humans, known as adjuvants, are of great interest for biomedical applications. Vaccines alone typically do not stimulate the immune system enough by themselves to create a strong and lasting immune response, so adjuvants are necessary to achieve long-term benefits. Cancer immunotherapies are another emerging technology relying on adjuvants to achieve a strong immune response to kill cancer cells.
Monophosphoryl lipid A (MPLA) and 2,4-dinitrophenyl (DNP) are two effective adjuvants. MPLA, being derived from bacteria, activates the antibacterial response pathway through its interaction with the toll-like receptor 4 (TLR4), a protein designed to recognize foreign antigens, including certain bacteria, e.g., Gram-negative bacteria. For its part, DNP can recruit its corresponding endogenous antibodies in the immune system, which in turn bind to the Fc receptors of immune cells to initiate a cytotoxic response to the incursion. The sugar rhamnose can also substitute for DNP to serve the same purpose, as it activates the same antibody-Fc receptor pathway while also providing the additional benefit of combatting tumor, making it a doubly effective ingredient in cancer immunotherapy. As a result, the covalent linkage of DNP or rhamnose with MPLA produces a multiplicative impact on the potency of the conjugate adjuvants.
