The present invention relates to a synthetic saccharide of general formulate (I) that is related to Clostridium difficile PS-II cell-surface polysaccharide and conjugate thereof. Said synthetic saccharide, said conjugate and pharmaceutical composition containing said synthetic saccharide or said conjugate are useful for prevention and/or treatment of diseases associated with Clostridium difficile. Furthermore, the synthetic saccharide of general formula (I) is useful as marker in immunological assays for detection of antibodies against Clostridium difficile bacteria.

The present invention is directed to an isolated synthetic tripeptide of formula H-D-Phe-N-Methyl-L-Val-L-Ala-OMe (SEQ ID NO:1), or a derivative thereof, and to the corresponding lipotripeptides, which are specific to Mycobacterium avium subsp. paratuberculosis (Map)S-type strain, as well as derivatives and conjugates thereof. The invention also concerns the use of these antigens in different methods and tests for detecting Map infection, especially by detecting humoral response and cell mediated response of infected animals. The invention is also directed to a genetic signature of Map and a mass spectrometry and NMR spectroscopy signature of Map presence or infection.

Modified hepatitis C virus polypeptides are described. The polypeptides include the HCV NS4a domain and modified NS3 domain. The polypeptides retain conformational epitopes. HCV immunoassays including the polypeptides are also described.

The invention concerns soluble and antigenic HTLV p24 variants that can be fused to chaperones and their use in diagnostic applications such as immunoassays for detecting antibodies against HTLV-I or HTLV-II in an isolated biological sample. In particular, the invention relates to a soluble HTLV-I or HTLV-II p24 antigen comprising either the N- or the C-terminal domain of p24 and lacking the other domain. Moreover, the invention covers recombinant DNA molecules encoding these HTLV-I and -II fusion antigens as well as their recombinant production using expression vectors and host cells transformed with such expression vectors. In addition, the invention focuses on compositions of these HTLV p24 antigens with HTLV gp21 antigen and on an immunoassay method for detection of HTLV antibodies using the antigens of the invention. Also the use of HTLV p24 antigens in an in vitro diagnostic assay as well as a reagent kit for detection of anti-HTLV-antibodies comprising said HTLV antigens is encompassed.

A microfluidic device can comprise at least one swept region that is fluidically connected to unswept regions. The fluidic connections between the swept region and the unswept regions can enable diffusion but substantially no flow of media between the swept region and the unswept regions. The capability of biological micro-objects to produce an analyte of interest can be assayed in such a microfluidic device. Biological micro-objects in sample material loaded into a microfluidic device can be selected for particular characteristics and disposed into unswept regions. The sample material can then be flowed out of the swept region and an assay material flowed into the swept region. Flows of medium in the swept region do not substantially affect the biological micro-objects in the unswept regions, but any analyte of interest produced by a biological micro-object can diffuse from an unswept region into the swept region, where the analyte can react with the assay material to produce a localized detectable reaction. Any such detected reactions can be analyzed to determine which, if any, of the biological micro-objects are producers of the analyte of interest.

HIV-1 Env ectodomain trimers stabilized in a prefusion mature closed conformation and methods of their use and production are disclosed. In several embodiments, the HIV-1 Env ectodomain trimers and/or nucleic acid molecules can be used to generate an immune response to HIV-1 in a subject. In additional embodiments, the therapeutically effective amount of the HIV-1 Env ectodomain trimers can be administered to a subject in a method of treating or preventing HIV-1 infection.

Sensitive detection of IgG antibodies against SARS-CoV-2 is important to assessing immune responses to viral infection or vaccination and immunity duration. Antibody assays using non-invasive body fluids such as saliva could facilitate mass testing including young children, elderly and those who resist blood draws, and easily allowing longitudinal testing/monitoring of antibodies over time. Here, we developed a new lateral flow (nLF) assay that sensitively detects SARS-CoV-2 IgG antibodies in the saliva samples of vaccinated individuals and previous COVID-19 patients. The 25 minutes nLF assay detected anti-spike protein (anti-S1) IgG in saliva samples with 100% specificity and high sensitivity from both vaccinated (99.51% for samples ≥19 days post 1st Pfizer or Moderna mRNA vaccine dose) and infected individuals. Antibodies against nucleocapsid protein (anti-NCP) was detected only in the saliva samples of COVID-19 patients and not in vaccinated samples, allowing facile differentiation of vaccination from infection. Salivary SARS-CoV-2 anti-S1 IgG antibodies correlated with that in matched dried blood spot (DBS) samples measured by a quantitative pGOLD™ lab-test, showing similar evolution trends post vaccination. The new salivary rapid test platform is applicable to non-invasive detection of antibodies against infection and vaccination for a wide range of diseases.

The invention provides compositions (e.g., peptide compositions) useful for the detection of antibodies that bind to Borrelia antigens. The peptide compositions comprise polypeptide sequences comprising variants in the IR6 domain of the Borrelia VlsE protein. The invention also provides devices, methods, and kits comprising such peptide compositions and useful for the detection of antibodies that bind to Borrelia antigens and the diagnosis of Lyme disease.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the strain of coronavirus that causes coronavirus disease 2019 (COVID-19), the respiratory illness responsible for the COVID-19 pandemic. Antibodies produced from an immune response against SARS-CoV-2 infection are used to analyze prior exposure to the virus. The present invention provides methods for detecting antibodies in response to SARS-CoV-2 infection in a single multiplex immunoassay.

The present invention provides compositions and methods of use comprising a chimeric dengue virus E glycoprotein comprising a dengue virus E glycoprotein backbone, which comprises amino acid substitutions that may introduce an epitope that is recognized by an antibody from a dengue virus serotype that is different from the dengue virus serotype of the dengue virus E glycoprotein backbone.