Abstract: The invention identifies the CTLA4 receptor as a ligand for the B7 antigen. The complete amino acid sequence encoding human CTLA4 receptor gene is provided. Methods are provided for expressing CTLA4 as an immunoglobulin fusion protein, for preparing hybrid CTLA4 fusion proteins, and for using the soluble fusion proteins, fragments and derivatives thereof, including monoclonal antibodies reactive with B7 and CTLA4, to regulate T cell interactions and immune responses mediated by such interactions.

Abstract: This invention relates to novel lactams having drug and bio-affecting properties, their pharmaceutical compositions and methods of use. These novel compounds inhibit the processing of amyloid precursor protein and, more specifically, inhibit the production of A&bgr;-peptide, thereby acting to prevent the formation of neurological deposits of amyloid protein. More particularly, the present invention relates to the treatment of neurological disorders related to &bgr;-amyloid production such as Alzheimer's disease and Down's Syndrome.

Abstract: This invention relates to a novel method of screening for inhibitors of beta-amyloid production, and thereby identifying such inhibitors as therapeutics for neurological and other disorders involving APP processing and beta-amyloid production. This invention also relates to identifying macromolecules involved in APP processing and beta-amyloid production. Furthermore, inhibitors identified by the screening method of the present invention are useful in the treatment of neurological disorders, such as Alzheimer's disease, which involve elevated levels of A&bgr; peptides.