Described herein are, proteins comprising amino acid substitutions in at least one of a first and a second polypeptide chain. Furthermore, is described the uses and methods related to said proteins.

The present invention relates to antibody molecules that bind to Wall Teichoic Acid (WTA) or Capsular Polysaccharides (CP) such as Capsular Polysaccharides type 5 (CP5). The invention relates in particular to antibody molecules of the IgG isotype having a mutation in the Fc domain that enhances clustering of IgG molecules after target binding. The invention also relates to pharmaceutical compositions containing these molecules and the treatment of infectious diseases using these compositions

Provided are an antibody that binds to Staphylococcus aureus alpha-hemolysin or a fragment thereof, and the use of the antibody or the fragment thereof for preventing or treating Staphylococcus aureus infections. The antibody is obtained through screening by means of the strategies of attenuated immunity and virulent screening of alpha-hemolysin, and the antibody has high affinity to alpha-hemolysin, can effectively block the hemolysis effect of alpha-hemolysin, has proved significant protective or therapeutic effects in the alpha-hemolysin sepsis model, MRSA bacteremia model and MRSA lung infection model, and has a synergistic effect with antibiotics, which is a beneficial supplement to existing antibiotic therapy for Staphylococcus aureus.

The invention relates to a method of isolating an immunoglobulin, comprising the steps of: a) providing a separation matrix comprising multimers of immunoglobulin-binding alkali-stabilized Protein A domains covalently coupled to a porous support, b) contacting a liquid sample comprising an immunoglobulin with the separation matrix, c) washing said separation matrix with a washing liquid, d) eluting the immunoglobulin from the separation matrix with an elution liquid, and e) cleaning the separation matrix with a cleaning liquid,
wherein the alkali-stabilized Protein A domains comprise mutants of a parental Fc-binding domain of Staphylococcus Protein A (SpA), as defined by SEQ ID NO: 51 or SEQ ID NO: 52, wherein the amino acid residues at positions 13 and 44 of SEQ ID NO: 51 or 52 are asparagines and wherein at least the asparagine residue at position 3 of SEQ ID NO: 51 or 52 has been mutated to an amino acid selected from the group consisting of glutamic acid, lysine, tyrosine, threonine, phenylalanine, leucine, isoleucine, tryptophan, methionine, valine, alanine, histidine and arginine.

The invention discloses a method for separation of antibodies or antibody fragments, comprising the steps of: a) providing a feed comprising antibodies or antibody fragments having a VH3 region and being devoid of an Fc region capable of binding to Protein A; b) contacting the feed with a separation resin having covalently coupled ligands, wherein the ligands comprise a polypeptide as defined by SEQ ID NO 1 and wherein the antibodies or antibody fragments bind to the separation resin; c) optionally washing the separation resin with a washing liquid; d) eluting the antibodies or antibody fragments from the separation resin with an elution liquid and recovering the antibodies or antibody fragments.

The present invention concerns methods and compositions for treating or preventing a bacterial infection, particularly infection by a Staphylococcus bacterium. The invention provides methods and compositions for stimulating an immune response against the bacteria. In certain embodiments, the methods and compositions involve a non-toxigenic Protein A (SpA) variant.

This disclosure provides isolated or recombinant polypeptides that are useful to vaccinate individuals suffering from chronic/recurrent biofilm disease or as a therapeutic for those with an existing infection. The individual's immune system will then naturally generate antibodies which prevent or clear these bacteria from the host by interfering with the construction and or maintenance of a functional protective biofilm. Alternatively, antibodies to the polypeptides can be administered to treat or prevent infection. Bacteria that are released from the biofilm by our technology are more readily cleared by the remainder of the host's immune system.

The present invention provides for methods of preventing and/or treating S. aureus-associated bacteremia and sepsis, and methods for preventing and/or treating S. aureus-associated pneumonia in immunocompromised patients using anti-S. aureus alpha-toxin (anti-AT) antibodies. Also provided are methods of reducing S. aureus bacterial load in the bloodstream or heart of a mammalian subject comprising administering to the subject an effective amount of an isolated anti-S. aureus alpha toxin (anti-AT) antibody or antigen-binding fragment thereof. Methods of reducing S. aureus bacterial agglutination and/or thromboembolic lesion formation in a mammalian subject comprising administering to the subject an effective amount of an isolated anti-S. aureus alpha toxin (anti-AT) antibody or antigen-binding fragment thereof, are also provided. Also provided are methods of preventing or reducing the severity of S. aureus associated pneumonia in an immunocompromised mammalian subject.

Herein is reported a polypeptide comprising a first polypeptide and a second polypeptide each comprising in N-terminal to C-terminal direction at least a portion of an immunoglobulin hinge region, which comprises one or more cysteine residues, an immunoglobulin CH2-domain and an immunoglobulin CH3-domain, wherein the first, the second, or the first and the second polypeptide comprise the mutation Y436A (numbering according to the EU index).

Herein is reported a heterodimeric polypeptide comprising a first polypeptide comprising in N-terminal to C-terminal direction at least a portion of an immunoglobulin hinge region, which comprises one or more cysteine residues, an immunoglobulin CH2-domain and an immunoglobulin CH3-domain, and a second polypeptide comprising in N-terminal to C-terminal direction at least a portion of an immunoglobulin hinge region, which comprises one or more cysteine residues, an immunoglobulin CH2-domain and an immunoglobulin CH3-domain, wherein the first polypeptide comprises the mutations Y349C, T366S, L368A and Y407V (hole-chain) and the second polypeptide comprises the mutations S354C and T366W (knob-chain), and wherein the first polypeptide (hole-chain) comprises the mutations i) I253A or I253G, and ii) L314A or L314G or L314D, and wherein the first polypeptide and the second polypeptide are connected by one or more disulfide bridges, and wherein the CH3-domain of the first polypeptide and the CH3-domain of the second polypeptide both bind or both do not bind to protein A (numbering according to the Kabat EU index).