Abstract: A single-stranded nucleic acid molecule which encodes an amino acid sequence comprising at least a portion of a T4 glycoprotein is provided. Additionally, amino acid sequences which comprise at least a portion of a T4 glycoprotein and are useful as a prophylaxis for treating a subject with acquired immune deficiency syndrome are provided. These amino acid sequences, which are capable of specifically forming a complex with a human immunodeficiency virus envelope glycoprotein and which are soluble in an aqueous solution may be administered to a subject infected with a human immunodeficiency virus so as to block the human immunodeficiency virus from binding to T4+ cells. Monoclonal antibodies directed to the water-soluble amino acid sequences of the present invention may be used as vaccines for immunizing a subject against acquired immune deficiency syndrome.

Abstract: Retroviral vectors which are resistant to inactivation by human serum. The retroviral vectors are produced in a cell line which is resistant to lysis by human serum, such cell lines including the HOS, Mv-1-Lu, HT1080, TE671, and human 293 cell lines, as well as cell lines derived therefrom. Such retroviral vectors are especially useful as in vivo gene delivery vehicles.

Abstract: The present invention is based upon the finding that porcine endogenous retroviruses exist in two different subtypes, which we have termed PERV-A and PERV-B. The differences are reflected in sequence divergence in the envelope genes, and these differences may be used to provide nucleic acid and antibody probes which can distinguish between the two subtypes. This allows patterns of subtype transmission between cells, particularly porcine to human cells, to be monitored.

Abstract: This invention provides an isolated single-stranded nucleic acid which encodes an aqueous-soluble polypeptide comprising at least a portion of a human T4 glycoprotein, which portion specifically forms a complex with a human immunodeficiency virus envelope glycoprotein.

Abstract: A single-stranded nucleic acid molecule which encodes an amino acid sequence comprising at least a portion of a T4 glycoprotein is provided. Additionally, amino acid sequences which comprise at least a portion of a T4 glycoprotein and are useful as a prophylaxis for treating a subject with acquired immune deficiency syndrome are provided. These amino acid sequences, which are capable of specifically forming a complex with a human immunodeficiency virus envelope glycoprotein and which are soluble in an aqueous solution may be administered to a subject infected with a human immunodeficiency virus so as to block the human immunodeficiency virus from binding to T4.sup.+ cells.Monoclonal antibodies directed to the water-soluble amino acid sequences of the present invention may be used as vaccines for immunizing a subject against acquired immune deficiency syndrome.

Abstract: Retroviral which are resistant to inactivation by human serum. The retroviral vectors are produced in a cell line which is resistant to lysis by human serum, such cell lines including the HOS, Mv-1-Lu, HT1080, TE671, and human 293 cell lines, as well as cell lines derived therefrom. Such retroviral vectors are especially useful as in vivo gene delivery vehicles.

Abstract: A single-stranded nucleic acid molecule which encodes the amino acid sequence comprising at least a portion of a T4 glycoprotein is provided. Additionally, amino acid sequences which comprise at least a portion of a T4 glycoprotein and are useful as a prophylaxis for treating a subject with acquired immune deficiency syndrome are provided. These amino acid sequences, which are capable of specifically forming a complex with a human immunodeficiency virus glycoprotein and which are soluble in an aqueous solution may be administered to a subject infected with a human immunodeficiency virus so as to block the human immunodeficiency virus from binding to T4 cells. Monoclonal antibodies directed to the water-soluble amino acid sequences of the present invention may be used as vaccines for immunizing a subject against acquired immune deficiency syndrome.

Abstract: A single-stranded nucleic acid molecule which encodes an amino acid sequence comprising at least a portion of a T4 glycoprotein is provided. Additionally, amino acid sequences which comprise at least a portion of a T4 glycoprotein and are useful as a prophylaxis for treating a subject with acquired immune deficiency syndrome are provided. These amino acid sequences, are capable of specifically forming a complex with a human immunodeficiency virus envelope glycoprotein and which are soluble in an aqueous solution. Monoclonal antibodies directed to the water-soluble amino acid sequences of the present invention may be used as vaccines for immunizing a subject against acquired immune deficiency syndrome.

Abstract: Samples e.g. transfusion blood, are assayed for antibodies to retroviruses, e.g. AIDS virus, using an insolubilized antigen comprising retrovirus antigens bound to globulin, the globulin itself being bound to an inert solid support; and an immunoglobulin which contains specific antibody to the retrovirus antigens and which is labelled with a revealing label, and the soluble phase is then separated from the insoluble phase and the quantity of revealing label associated with either the soluble or the insoluble phase determined.The sue of labelled antibody in competition with test sera for binding on the insolublized antigen permits better identification of antibody containing specimens. The retroviruses may be a human T-lymphotropic retrovirus HTLV-I, II or III or a new retrovirus isolate CBL-1 etiologically related to AIDS.