The present application provides a method of diagnosing bacterial infections using engineered glycoproteins in an immunoassay. The engineered bacterial glycoproteins used in the immunoassay comprise a bacterial antigen covalently attached to a protein via polysaccharyltransferase (PTase)-mediated glycosylation, wherein the bacterial antigen is selected based on the bacterial infection of interest. Antibodies in a bodily fluid of subjects infected with a bacteria will bind to the engineered glycoprotein, and the resulting binding complexes are detected or quantitated.

There is provided a method of detecting in a sample the presence of an anti-M and/or anti-A and/or anti-C/Y antibody, the method comprising contacting the sample with a diagnostic conjugate provided according to the invention, comprising an oligosaccharide which comprises at least two units of 4,6-dideoxy-4-acylamido-α-pyranose and comprising at least one -(1-3)-link between adjacent 4,6-dideoxy-4-acylamido-α-pyranose units, in which the carbon at position 5 in the pyranose is linked to an R group, where R is independently selected from —CH.sub.2OH, —H or an alkyl group having at least one C atom, the oligosaccharide being covalently linked to a non-saccharide molecule or to a surface.

Methods and compositions for the treatment of Brucella induced diseases and disorders are disclosed herein. In preferred embodiments, the invention relates to vaccines. In additional embodiments, the invention relates to formulations capable of releasing said vaccines at a controlled rate of release in vivo. In further embodiments, the invention relates to modified strains of the bacteria Brucella melitensis and Brucella abortus. In still further embodiments, the invention relates to compositions that do not induce clinical symptoms or splenomegaly in a subject receiving said compositions.

There is provided a molecule comprising a chain of seven or more contiguous units of 4,6-dideoxy-4-acylamido-α-pyranose each pair of units joined by a C.sub.1-C.sub.2 or a C.sub.1-C.sub.3 link, the chain having a terminal end and a reducing end, wherein the pyranose ring in the unit of the chain most distal from the reducing end is linked to a cap structure. The cap structure is not a 4,6-dideoxy-4-acylamido-α-pyranose. There are also provided vaccine compositions comprising the molecule and methods of vaccinating an animal against infection by a Brucella organism, including methods of distinguishing between a vaccinated and an infected animal. There are further provided novel methods of detecting the presence in a sample of an anti-Brucella antibody.

There is provided a molecule comprising a chain of seven or more contiguous units of 4,6-dideoxy-4-acylamido-α-pyranose, each pair of units joined by a C.sub.1-C.sub.2 or a C.sub.1-C.sub.3 link, the chain having a terminal end and a reducing end, wherein the pyranose ring in the unit of the chain most distal from the reducing end is linked to a cap structure. The cap structure is not a 4,6-dideoxy-4-acylamido-α-pyranose. There are also provided vaccine compositions comprising the molecule and methods of vaccinating an animal NI against infection by a Brucella organism, including methods of distinguishing between a vaccinated and an infected animal. There are further provided novel methods of detecting the presence in a sample of an anti-Brucella antibody.

A diagnostic kit for a confirmatory assay using the indirect ELISA method that measures the levels of anti-Native Hapten antibodies produced during a real infection, thereby preventing large financial losses to livestock farm, by discerning false positives that present anti-LPS antibodies due to doss-reactions with enterobacteria and post-vaccinal antibodies for the diagnosis of bovine brucellosis in blood serum and individual milk (per animal) and bulk milk (tank), characterised by using the crude Native Hapten antigen, extracted from B. melitensis 16M strain, with no purification treatment and an effective adherence capacity, which is used to antigenize plates at a known concentration (1 g per well), where using as reference positive and negative controls subjected to the lyophilisation (freeze drying) method to ensure their preservation, thereby avoiding the contamination and degradation of the antibodies present and ensuring the stability of the optical densities in said controls for a correct results interpretation of an indirect ELISA, are taken as reference. The lyophilisation method for controls that may be used in other diagnostic methods is also presented.

There is provided a molecule comprising a chain of seven or more contiguous units of 4,6-dideoxy-4-acylamido--pyranose, each pair of units joined by a C.sub.1-C.sub.2 or a C.sub.1-C.sub.3 link, the chain having a terminal end and a reducing end, wherein the pyranose ring in the unit of the chain most distal from the reducing end is linked to a cap structure. The cap structure is not a 4,6-dideoxy-4-acylamido--pyranose. There are also provided vaccine compositions comprising the molecule and methods of vaccinating an animal NI against infection by a Brucella organism, including methods of distinguishing between a vaccinated and an infected animal. There are further provided novel methods of detecting the presence in a sample of an anti-Brucella antibody.

Methods and compositions for the treatment of Brucella induced diseases and disorders are disclosed herein. In preferred embodiments, the invention relates to vaccines. In additional embodiments, the invention relates to formulations capable of releasing said vaccines at a controlled rate of release in vivo. In further embodiments, the invention relates to modified strains of the bacteria Brucella melitensis and Brucella abortus. In still further embodiments, the invention relates to compositions that do not induce clinical symptoms or splenomegaly in a subject receiving said compositions.

There is provided a molecule comprising a chain of seven or more contiguous units of 4,6-dideoxy-4-acylamido-?-pyranose each pair of units joined by a C.sub.1-C.sub.2 or a C.sub.1-C.sub.3 link, the chain having a terminal end and a reducing end, wherein the pyranose ring in the unit of the chain most distal from the reducing end is linked to a cap structure. The cap structure is not a 4,6-dideoxy-4-acylamido-?-pyranose. There are also provided vaccine compositions comprising the molecule and methods of vaccinating an animal against infection by a Brucella organism, including methods of distinguishing between a vaccinated and an infected animal. There are further provided novel methods of detecting the presence in a sample of an anti-Brucella antibody.

Methods and compositions for the treatment of Brucella induced diseases and disorders are disclosed herein. In preferred embodiments, the invention relates to vaccines. In additional embodiments, the invention relates to formulations capable of releasing said vaccines at a controlled rate of release in vivo. In further embodiments, the invention relates to modified strains of the bacteria Brucella melitensis and Brucella abortus. In still further embodiments, the invention relates to compositions that do not induce clinical symptoms or splenomegaly in a subject receiving said compositions.