Abstract: An expression library comprising a repertoire of nucleic acid sequences each encoding at least part of a variable domain of a heavy chain derived from an immunoglobulin naturally devoid of light chains and its use in producing antibodies, particularly fragments thereof, is disclosed. The invention provides a method for preparing antibodies, or fragments thereof, having a specificity for a target antigen which avoids the need for the donor previously to have been immunised with the target antigen.

Abstract: A method of inhibiting viral infection using a monovalent antigen binding protein comprising a single domain binding unit capable of binding to a virus is described. Preferably the protein is a heavy chain variable domain derived from an immunoglobulin naturally devoid of light chains. Food, pharmaceutical and cosmetic products comprising such proteins are also described together with a method for selecting inhibiting proteins from a large population of mainly containing non-inhibiting, but infectious agent binding fragments.

Abstract: A method of inhibiting viral infection using a monovalent antigen binding protein comprising a single domain binding unit capable of binding to a virus is described. Preferably the protein is a heavy chain variable domain derived from an immunoglobulin naturally devoid of light chains. Food, pharmaceutical and cosmetic products comprising such proteins are also described together with a method for selecting inhibiting proteins from a large population of mainly containing non-inhibiting, but infectious agent binding fragments.

Abstract: A method of inhibiting viral infection using a monovalent antigen binding protein comprising a single domain binding unit capable of binding to a virus is described. Preferably the protein is a heavy chain variable domain derived from an immunoglobulin naturally devoid of light chains. Food, pharmaceutical and cosmetic products comprising such proteins are also described together with a method for selecting inhibiting proteins from a large population of mainly containing non-inhibiting, but infectious agent binding fragments.

Abstract: New products are provided comprising inactivated lower eukaryotic cells, preferably yeasts or molds, having at the outer surface functionally active antibodies or functionally active fragments thereof. Preferred antibody fragments are the variable domains of Camelidae heavy chain antibodies, which are surprisingly stable against physical and chemical decontamination regimes and do not loose their activity when they are immobilized on the glucan layer of the cell wall which is present in a variety of lower eukaryotes. The new products are preferably in the field of food products, personal care products, and animal feed products.