Press Release

A New Type of Vaccine Adjuvant Which Utilizes Nano-Particle of Pullulan Derivative and Cytokine - A Protective Effects against Influenza Virus Infection have been Confirmed in Animal Experiments -



Hayashibara Co., Ltd. (headquarters in Okayama, Okayama-shi, Okayama, Japan; President, Reiji NAGASE) announced that a new effective and stable vaccine adjuvant formulation containing of TNF, a kind of cytokine, pre-encapsulated into nano-particles of pullulan derivatives, has been developed. Intranasal administration of the formulation significantly augmented antibody production of conventional influenza virus and protected mice against lethal influenza virus infection. The formulation would be very convenient because it eventually augmented vaccine effectiveness by nasal administration which has not been applied to the conventional vaccine. Hence, the nano-particle is expected to be a useful tool in the development of an advanced vaccine therapy against various pathogens as well as influenza virus. Hayashibara will present the results of this research at the 133rd Annual Meeting of the Pharmaceutical Society of Japan (March 27 - 30, at Pacifico Yokohama, Yokohama, Kanagawa Prefecture).

Please direct any inquiries about this research or our business to: (c/o) Watanabe, Research and Development Division, Hayashibara Co., Ltd.

- Research objective
It is well known that vaccines have played an important role in preventing infectious diseases. Since vaccines which are mainly formulated with antigens (attenuated or detoxified pathogens) do not exert a sufficient effect in some cases, adjuvants are added thereto in vaccine formulation to enhance their immune response. Considering the fact that conventional vaccine formulations are mostly administered by injection, in addition, there is an urgent need to develop a new vaccine formulation which is highly convenient and can be administered intranasally and so on. In this report, Hayashibara has combined polysaccharide, pullulan derivative, and TNF, a cytokine, to produce a new nano-particle formulation. We investigated its effect as an intranasal administered vaccine adjuvant in lethal influenza virus-infected mice.

- Test Method
An inactivated influenza virus vaccine was intranasally administered to mice either alone or in combination with the TNF nano-particle adjuvant once a week for 3 weeks. Subsequently, they were infected with a lethal influenza virus and the survival rate was examined. All mice died when given the influenza vaccine alone, however, 90% of mice survived when given the vaccine in combination with the TNF nano-particle adjuvant under the same conditions. As a result, protective effect against influenza virus infection was confirmed (see the figure below). Furthermore, in addition to the histopathological findings, there were no cases of death or systemic toxicity due to the administration of the TNF nano-particle adjuvant; we have concluded that there are few concerns about its immunotoxicity.

- Conclusion
We confirmed that the TNF nano-particle adjuvant strongly augmented the effectiveness of the vaccine by intranasal administration and protected mice against the lethal influenza virus infection.

- Future possibilities
The TNF nano-particle adjuvant is expected to be a useful adjuvant in the development of a highly convenient and effective next-generation vaccine therapy for various pathogens as well as the influenza virus. Hayashibara will explore possibilities of research or business partners toward practical application of the TNF nano-particle adjuvant.


We commercialized for the first time in the world; A type of water-soluble polysaccharide produced from starch syrup by fermentation using a type of filamentous bacteria which is also referred to as black yeast. It is widely used as thickener and a base for edible films in food and cosmetics. Pulluan is listed as a pharmaceutical additive in the Japanese Pharmacopoeia. As one of applications of pullulan, a new DDS (drug delivery system) material has been developed.

It is substance which augments the immune response when administered with an antigen.

TNF (Tumor Necrosis Factor)
This is one of cytokines which are known to be involved in prevention of infectious diseases by acting in the immune system. We have improved its stability and safety by encapsulation into nano-particles using a pullulan derivative.

Cytokines are protein molecules that are secreted by numerous cells and are known to be mainly involved in immune function.

It is a general term of particle with a diameter in the order of nanometers (one-ten-millionth of a meter to one-billionth of a meter). Some nano-particles permit new functions and properties to the molecules by changing their size and structure. In the case of the TNF nano-particle adjuvant, stabilization and controlled-release of encapsulated TNF were achieved. (1 nano-meter is 1-billionth of a meter.)

Intranasal administration
It is one of the methods to administer a drug in place of the conventional injection. Patients will feel less pain and less feeling of burden. It can even be administered by non-medical specialists and is expected as a new method of drug administration.

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