Abstract: Novel humanized immunoglobulins and active fragments thereof which are specifically reactive to Fas ligand are provided, and a site on Fas ligand which is important to inhibit apoptosis induced by the Fas-Fas ligand interaction against Fas-expressing cells is demonstrated. The novel humanized immunoglobulins and active fragments thereof which are specifically reactive to Fas ligand are prepared from hybridomas which produce monoclonal antibodies specifically reactive to Fas ligand, via recombinant DNA techniques. The humanized immunoglobulins can inhibit the physiological reactions between Fas ligand and Fas such as apoptosis. Further, identification of the site which is on Fas ligand and responsible for apoptosis induction allows creation of recombinant proteins or peptides which are specifically reactive to the amino acids within the site so as to inhibit apoptosis, and to find new therapeutic or diagnostic agents.

Abstract: A monoclonal antibody useful for clinical application which recognizes the conserved region of V3-PND region of glycoprotein antigen having a molecular weight of about 1.2.times.10.sup.5 daltons (gp120) on a coating membrane of human immunodeficiency virus (HIV) and which has an ability to neutralize a broad range of various HIV variants, or a fragment thereof, and the chimeric and humanized antibodies derived therefrom are provided. By using as an immunogen a plurality of peptides having PND-Tip region containing the highly conserved GPGR sequence within PND of HIV gp120, a monoclonal antibody having a neutralizing activity to many HIV variants can be prepared. By transplanting the gene fragment coding for the variable region of said monoclonal antibody or complementarity determining region (CDR) of said region to a human antibody gene, a chimeric antibody or a reshaped antibody having an anti-HIV neutralizing activity which are effective for clinical application can be obtained.

Abstract: A Gene fragment which comprises a DNA sequence coding for an amino acid sequence of a constant region of feline immunoglobulin .lambda. chain; a gene fragment which comprises a DNA sequence coding for an amino acid sequence of a constant region of feline immunoglobulin .kappa. chain; a gene fragment which comprises a DNA sequence coding for the constant region of feline immunoglobulin .gamma.

Abstract: A gene fragment which comprises a DNA sequence coding for an amino acid sequence of a constant region of canine immunoglobulin lambda chain; a gene fragment which comprises a DNA sequence coding for an amino acid sequence of a constant region of canine immunoglobulin kappa chain; a gene fragment which comprises a DNA sequence coding for the constant region of canine immunoglobulin gamma chain; a recombinant DNA molecule coding for an amino acid sequence of a mouse-dog chimeric antibody which comprises a gene fragment coding for an amino acid sequence of a variable region of a mouse immunoglobulin and a gene fragment coding for an amino acid sequence of a constant region of a canine immunoglobulin wherein the latter gene fragment; a polypeptide of a mouse-dog chimeric antibody which is expressed from a cell transformed with an expression vector for cells wherein said recombinant DNA molecule cording for an amino acid sequence of the mouse-dog chimeric antibody is incorporated; a dog-mouse heterohybridoma which

Abstract: The present invention relates to a gene fragment coding for a variable region of an antibody having a neutralizing activity against human immunodeficiency virus (HIV) and a process for preparing the same. A mouse-human chimeric antibody and a mouse-human reshaped antibody having a neutralizing activity against HIV can be prepared by obtaining a specific nucleotide sequence of a gene fragment coding for a variable region of H chain and L chain of an antibody having a neutralizing activity against HIV, and then artificially fusing DNAs synthesized based on these nucleotide sequences with a gene coding for a human immunoglobulin. The novel recombinant anti-HIV antibody of the present invention is useful for treatment and prevention of AIDS.

Abstract: A murine monoclonal antibody which specifically binds to a glycoprotein antigen having a molecular weight of about 12.times.10.sup.4 daltons (gp120) present in the envelope of human T-lymphotropic virus III.sub.MN (HTLV-III.sub.MN) and capable of neutralizing the HTLV-III.sub.MN as determined by in vitro inhibition of syncytium formation but does not bind to other HTLV-III strains, or antigen-binding fragments, which is useful for prophylaxis, treatment and diagnosis of AIDS.

Abstract: A gene fragment which comprises a DNA sequence coding for an amino acid sequence of a constant region of canine immunoglobulin lambda chain; a gene fragment which comprises a DNA sequence coding for an amino acid sequence of a constant region of canine immunoglobulin kappa chain; a gene fragment which comprises a DNA sequence coding for the constant region of canine immunoglobulin gamma chain; a recombinant DNA molecule coding for an amino acid sequence of a mouse-dog chimeric antibody which comprises a gene fragment coding for an amino acid sequence of a variable region of a mouse immunoglobulin and a gene fragment coding for an amino acid sequence of a constant region of a canine immunoglobulin; a polypeptide of a mouse-dog chimeric antibody which is expressed from a cell transformed with an expression vector for cells wherein said recombinant DNA molecule cording for an amino acid sequence of the mouse-dog chimeric antibody is incorporated; a dog-mouse heterohybridoma which produces canine immunoglobulin;

Abstract: A Gene fragment which comprises a DNA sequence coding for an amino acid sequence of a constant region of feline immunoglobulin .lambda. chain; a gene fragment which comprises a DNA sequence coding for an amino acid sequence of a constant region of feline immunoglobulin .kappa. chain; a gene fragment which comprises a DNA sequence coding for the constant region of feline immunoglobulin .gamma.

Abstract: Disclosed is a monoclonal antibody to HBsAg which is prepared by forming hybridomas between human peripheral blood lymphocyte cells, derived from humans having high titers of anti-HBsAg, and myeloma cells, cloning the hybridomas and selecting the antibody-producing clones. The monoclonal antibody can react with all the subtypes of HBsAg and is expected to be very effective in diagnosis and treatment of diseases due to the viral infection.