The provided technology is in the field of conjugating native, non-detergent extracted, outer membrane vesicles (nOMV) to antigens to form nOMV-antigen conjugates, which are particularly useful for immunogenic compositions and immunisation; processes for the preparation and use of such conjugates is also provided.

Antigenic molecules and compositions described herein protect against infection by typhoidal and non-typhoidal Salmonella serovars. Methods of immunization comprise the use of the antigenic molecules.

An enriched population of modified lipopolysaccharide (LPS) molecular species being: devoid of phosphate group at position C1 of the reducing end of their lipid A domain; and substituted at position C6′ of the non-reducing end of their lipid A domain by a hydrophilic moiety, with the proviso that the hydrophilic moiety is not a hydroxyl group. Also, compositions that include the enriched population of modified LPS and uses of naturally-occurring LPS molecular species and/or enriched population of modified LPS molecular species for treating and/or preventing cancer, inflammatory diseases or infectious diseases, and for stimulating an immune response or vaccinating a subject.

As disclosed herein, fructose-asparagine (F-Asn) is a primary nutrient utilized during Salmonella-mediated gastroenteritis. Engineered bacteria are disclosed that can compete with Salmonella for F-Asn and other nutrients and withstand Salmonella-induced inflammation. These bacterium can be used as probiotics to treat and prevent Salmonella-mediated gastroenteritis.

Disclosed herein are unique adjuvant compositions comprising an attenuated derivative of a self-destructing bacterial pathogen that undergoes lysis in vivo. In exemplary embodiments, the bacterial pathogen is a Salmonella spp. Also disclosed are methods for enhancing an immune response using the adjuvants disclosed herein.

In certain embodiments, a recombinant attenuated derivative of a pathogenic Salmonella enterica serovar typhi cell is provided, (a) wherein one or more genes encoding subunits of a stg operon (Salmonella typhi Δstg) are inactivated or deleted resulting in a decrease of Stg adhesin/fimbriae production as compared to genes encoding a wild-type Stg operon (stgABCC′D), and/or (b) the cell comprises a nucleic acid encoding at least one of a gene encoding a subunit of a long polar fimbriae (Lpf) of S. enterica serovar Typhimurium protein. In certain embodiments, vaccines and compositions, and methods of use of the recombinant attenuated derivative of a pathogenic Salmonella enterica serovar typhi cell are provided.

A recombinant Flagrp170 protein and pharmaceutical compositions comprising a Flagrp170 protein and related molecules encoding same, and cells presenting such a protein are provided. The Flagrp170 protein comprises an NF-.sub.KB-activating domain of Flagellin and an ATP-binding domain truncated Grp170. The pharmaceutical compositions of the invention can be used for the treatment or prevention of cancer or infectious disease.

A vaccine composition for birds comprising as an active ingredient a structure containing O-antigen derived from Gram-negative bacteria, provided that said structure does not contain a whole cell, and a process for preparing the same are provided. By using a structure containing O-antigen (e.g. lipopolysaccharide) derived from Gram-negative bacteria as an active ingredient in accordance with the present invention, alleviation of inoculation reaction and reduction in an amount of injection are attained as compared to the conventional whole-cells vaccine to thereby allow for the increase in the number of other antigens to be mixed therewith.

The invention provides in part methods of treating cancers of a specific organ or tissue by administering a composition that is antigenically specific for one or more microbes that are pathogenic in the specific organ or tissue in which the cancer is situated.

The present disclosure relates generally to compositions, dosage forms, and methods for preventing and treating infections. The compositions include intact and substantially non-viable Gram-negative bacterial cells which have been treated to reduce lipopolysaccharide (LPS)-associated endotoxin activity, which surprisingly have increased activity to trigger immune cell production of cytokines.