Title:  Immunopotentiating formulations for vaccinal use

United States Patent:  6,355,414

Assignee:  Centro de Ingenieria Genetica y Biotechnologia (Havana, CU)

Filed:  January 6, 2000

PCT NO:  PCT/CU98/00003

102(e) Date:  January 6, 2000

PCT PUB. Date:  September 11, 1998

Foreign Application Priority Data:  Mar 06, 1997[CU] (27/97)

The present invention is related to the field of medicine, particularly to the use of new adjuvant formulations with vaccine antigens. The technical objective pursued with this invention is, precisely, the development of formulations that are able to increase and/or modulate the immune response of the organism to vaccine antigens in the serum and the mucous lining. With this aim, a formulation was developed that contained as the main components the surface antigen of the hepatitis B virus and the acemannan in adequate proportions. As an extension of this result, formulations were developed in which a) HBsAg was used as the homologous or heterologous antigen carrier b) delivery systems of particulated antigens and c) soluble antigens, combined with the acemannan in specific proportions. The formulations of this invention are applicable in the pharmaceutical industry as vaccine formulations for human and veterinary use.

DISCLOSE OF THE INVENTION

The present invention is related to a vaccine formulation for nasopharyngeal administration, having as its main components subunit particulated antigens and the acemannan, in adequate proportions.

The novelty of this invention is due to the properties resulting from its nasopharyngeal administration, these are: to generate a systemic immunity of similar intensity and higher quality for similar antigen doses to that obtained with conventional vaccine formulations using aluminum hydroxide as the adjuvant. Also, a strong mucosal response is generated, which is not obtained by systemic inoculations of the antigen.

This is the first time that the use of the HBsAg is reported as antigen delivery system through the nasopharyngeal route combined with acemannan. With this system a proportionally increased response was obtained for the epitopes displayed on its surface in relation to the response obtained without using HBsAg as particulating system. This finding allows the formulation of combined vaccines using the HBsAg as an antigen delivery system through the mucous. Different in concept of the carrier activity as T cell bearing molecule capable of enhancing a T cell response against the antigen conjugated. It also supports the use of this strategy for the soluble antigen-particulated antigen combination and its use with polysaccharides with these characteristics through mucosal inoculation routes.

Here, it was generalized that liquid formulations of particulated (non-inactivated, non alive) antigen delivery systems together with the acemannan, inoculated by the nasopharyngeal route, preferentially potentiated the immune response in relation to the soluble antigen until the level of serological response obtained by the systemic route with alum. In the present invention the immunological modulator activity of combined formulations of antigen-acemannan are also described.

At present, the action mechanisms of the acemannan and other immunological stimulators polysaccharides are not completely clear. A possible mechanism could be related with the macrophages and dendritic cells, that have specific receptors for mannose and fucose increasing phagocytosis after antigen entrance. The antigenic assimilation at the nasopharyngeal level and more specifically at the Waldeyer ring--according to the assimilation mechanism for stratified epithelial tissue--can be potentiated with the activation of the macrophages and dendritic cells found in the area and with the attraction toward this zone of an increased number of immunological competent cells.

The particulation of the subunit (non inactivated and non living antigens), through conjugations to particulated antigens or their inclusion or association to delivery systems of antigens, constitutes a first step in antigen processing in this invention, the second step is the addition of the polysaccharide that activates the immune system. Special cases of this invention are those antigens particulated per se. This kind of antigens avoid the use of a particulated antigen delivery system, we have the example of hepatitis B surface antigen and are different to living or inactivated antigens.

The viscous consistency of the acemannan makes it an active vehicle that increases the time of antigen presence at the inoculation site. Other activities as the induction of the cytokines, the activation of mechanisms for antigen uptake by the M cell, the recruitment of different populations of cells from the immunological system and the increase of the antigen presenting activity, are not discarded. But these properties per se are not enough to induce an immune response through the nasopharingeal route.

The formulation, which is the object of this invention, presents, according to the size of the species to be immunized, an amount of inoculum able to cover the nasopharyngeal area up to the subglotis. The dose may be divided in 2 parts for its application or it may be introduced once. The concentration of the polysaccharide used ranged from 1 mg/mL to 9 mg/mL of lyophilized weight corresponding approximately to 0.070-0.600 mg/mL (in total hexose content measured by the antrone method). In spite of this broad range of concentrations, all of them are not capable of inducing optimum responses, at higher doses the responses are affected due to the polysaccharide viscosity, the presence of contaminants from lower molecular weights decrease the acemannan concentration, and the effectiveness of the resulting formulation. The purification method reported permits the higher purity of acemannan and thus its possible to achieve the higher responses. Furthermore this pure polysaccharide will be less reactogenic for humans.

Claim 1 of 15 Claims

What is claimed is:

1. A method for potentiating an immune response to antigens comprising:

administering a formulation comprising a subunit particulated antigen; and

acemannan polysaccharide, wherein the administration is by mucosal administration.

____________________________________________
If you want to learn more about this patent, please go directly to the U.S. Patent and Trademark Office Web site to access the full patent.