Abstract: The invention relates to a biologically-active peptide fragment of the Nef protein of human immunodeficiency virus, to pharmaceutical compositions comprising these peptides or biologically-active analogues thereof, to antagonists of the peptides and to pharmaceutical compositions comprising these antagonists, and to therapeutic and screening methods utilizing compounds and compositions of the invention.

Abstract: The present invention is directed toward immunologic- and nucleic acid-based methodologies for the detection of non-pathogenic human immunodeficiency virus type 1 (HIV-1) strains in the body fluids of HIV-infected individuals. A blood donor infected with HIV-1 and a cohort of six blood or blood product recipients infected from this donor were studied. These patients, who remained free of HIV-1-related disease and displayed stable and normal CD4 lymphocyte counts 10 to 14 years after infection, were termed long-term nonprogressors (LTNPs). The molecular characterization of HIV-1 sequences obtained from either virus isolates or patient peripheral blood mononuclear cells (PBMCs) of LTNPs identified similar deletions in the nef gene and in the region of overlap of nef and the U3 region of the long terminal repeat (LTR). These deletions corresponded to amino acids 166-206, or nucleotides 9281 to 9437, of the HIV-1.sub.NL43 nef/LTR region.

Abstract: This invention is directed toward non-pathogenic human immunodeficiency virus type 1 (HIV-1) strains containing deletions in the nef gene and U3 region of the long terminal repeat (LTR). A blood donor infected with HIV-1 and a cohort of six blood or blood product recipients infected from this donor were identified. These individuals, who remained free of HIV-1-related disease with stable and normal CD4.sup.+ lymphocyte counts 10 to 14 years after infection, were termed long-term nonprogressors (LTNPs). The molecular characterization of HIV-1 sequences obtained from either virus isolates or patient peripheral blood mononuclear cells (PBMCs) of LTNPs identified similar deletions in the nef gene and in the region of overlap of nef and the U3 region of the LTR. Full-length sequencing of one isolate genome and amplification of selected HIV-1 genome regions from other cohort members revealed no other abnormalities of obvious functional significance.

Abstract: A biologically-active peptide fragment of the Nef protein of human immunodeficiency virus is provided, pharmaceutical compositions comprising the peptide, analogs or derivatives of the peptide and therepeutic and screening methods which utilize the peptide and compositions which comprise them. The invention is particularly useful in the suppression of the immnune respons or in the suppression of symptoms of autoimmune disease.