Abstract: The present invention relates to novel complexes of major histocompability complex (MHC) molecules and uses of such complexes. In one aspect, the invention relates to single chain MHC class II complexes that include a class II &bgr;2 chain modification, e.g., deletion of essentially the entire class II &bgr;2 chain. In another aspect, the invention features single chain MHC class II which comprise an immunoglobin constant chain or fragment. Further provided are polyspecific MHC complexes comprising at least one single chain MHC class II molecule. MHC complexes of the invention are useful for a variety of applications including: 1) in vitro screens for identification and isolation of peptides that modulate activity of selected T cells, including peptides that are T cell receptor antagonists and partial agonists, and 2) methods for suppressing or inducing an immune response in a mammal.

Abstract: The present invention features novel binding molecules and methods of improving the specific binding affinity of binding molecules, which methods do not use X-ray crystallography. For example, in one aspect, the invention features methods of making antibodies with improved specific binding affinity for a polypeptide produced during prothrombin activation. The present invention is useful for a variety of applications including, e.g., producing binding molecules with improved binding affinity; and screening for binding molecules which are in low abundance.

Abstract: The invention includes antibodies that provide superior anti-coagulant activity by binding native human TF with high affinity and specificity. Antibodies of the invention can effectively inhibit blood coagulation in vivo. Antibodies of the invention can bind native human TF, either alone or present in a TF:VIIa complex, effectively preventing factor X binding to TF or that complex, and thereby reducing blood coagulation. Preferred antibodies of the invention specifically bind a conformational epitope predominant to native human TF, which epitope provides an unexpectedly strong antibody binding site.

Abstract: The present invention provides novel methods for the synthesis and isolation and purification of a peptide of interest (target peptide). In particular, the invention relates to peptide synthesis, isolation and purification methods that comprise use of penI fusion polypeptides and related gene fusion constructs that encode such polypeptides.

Abstract: The present invention relates to novel complexes of major histocompatibility complex (MHC) molecules and uses of such complexes. In one aspect, the invention relates to loaded MHC complexes that include at least one MHC molecule with a peptide-binding groove and a presenting peptide non-covalently linked to the MHC protein. In another aspect, the invention features single chain MHC class II peptide fusion complexes with a presenting peptide covalently linked to the peptide binding grove of the complex. MHC complexes of the invention are useful for a variety of applications including: 1) in vitro screens for identification and isolation of peptides that modulate activity of selected T cells, including peptides that are T cell receptor antagonists and partial agonists, and 2) methods for suppressing or inducing an immune response in a mammal.

Abstract: The present invention provides novel methods for the synthesis and isolation and purification of a peptide of interest (target peptide). In particular, the invention relates to peptide synthesis, isolation and purification methods that comprise use of penI fusion polypeptides and related gene fusion constructs that encode such polypeptides.

Abstract: The present invention relates to a fusion protein, comprising a pilin protein or a portion thereof and a heterologous polypeptide (target protein). In a preferred embodiment it relates to a method for displaying the target protein on the outer surface of a bacterial host cell capable of forming pilus. In certain embodiments, it is desirable that the pilus is a receptor for bacteriophage attachment and infection. The F pilus is preferred.

Abstract: A DNA sequence is described, which is a promoter for Streptomyces. This promoter is stronger than the wild type and ultimately increases transcription initiation and protein expression. Typically, a nucleotide base, such as guanine, is inserted into the promoter sequence between positions -50 and -75 to increase transcription initiation or protein expression. In a preferred embodiment, guanine is inserted between positions -62 and -63 of the promoter regulated by thiostrepton (tipA).

Abstract: A method and a cloning vector are described for the controlled accumulation of cloned heterologous gene products in Bacillus subtilis. The cloning vector is capable of being replicated in B. subtilis and includes the heterologous gene located and oriented such as to be under the control of an operator, promoter, and ribosome binding site sequence. The gene codes for a protein which is under the control of a transport mechanism by which the protein is secreted by the B. subtilis. The gene product is recovered from the growth medium for the B. subtilis. The cloning vector is also capable of similar use in other bacteria such as E. coli.

Abstract: The invention concerns a method for extending the half-life of mRNAs. The half-life extension is conferred upon the mRNA by a co-transcribed positive retroregulatory element which is ligated to the 3' end of the DNA sequence encoding the RNA. RNAs having an extended half-life conferred by a co-transcribed positive retroregulatory element are also claimed.

Abstract: The invention concerns positive retroregulatory elements, which when ligated to selected DNA sequences coding for a gene product, enhance the expression of the gene product. Plasmids carrying the positive retroregulatory element ligated to selected DNA sequence and cells transformed by such plasmids are provided AND claimed. In addition, the invention relates to a method for enhancing expression of a gene product by ligating a positive retroregulatory element to a selected DNA sequence expressionable for a desired gene product.

Abstract: The invention is a plasmid vector in which a first DNA sequence expressionable for a selected gene product is ligated to a positive retroregulatory element in a relationship thereto whereby expression of the selected gene product is enhanced. The first DNA sequence is furthermore operably linked to a second and third DNA sequence operably linked to one another which are respectively the P.sub.L promoter and a DNA sequence corresponding to an N gene ribosome binding site. Microorganisms transformed with the plasmid are also claimed.