Abstract: The present invention is directed to an Immunodeficiency-virus Suppressing Lymphokine (ISL) produced by stimulated CD8+ PBMC, cloning and isolation of nucleic acid molecules for eukaryotic ISL, and methods of treating viral infections with ISL. ISL is able to suppress the replication of viruses, especially retroviruses, in vitro and in vivo. More, specifically, a method is described for detecting a compound capable of inducing the expression of ISL by measuring the presence of ISL and the ability of ISL to inhibit HIV transcription.

Abstract: A nucleic acid with which expression of a polypeptide having interleukin-16 activity can be achieved or regulated in a prokaryotic or eukaryotic host cell, wherein in the region coding for the polypeptide, the nucleic acid (1) corresponds to the DNA sequence SEQ ID NOS:1 and 5-7 or its complementary strand; (b) hybridizes under stringent conditions with the DNA of sequence SEQ ID NOS:1 and 5-7; (c) or is a nucleic acid sequence which, if there was no degeneracy of the genetic code, would hybridize under stringent conditions with the nucleic acid sequences defined by (a) and (b); (d) and, if it codes for a polypeptide having interleukin-16 activity, is suitable as genomic DNA for the recombinant production of IL-16 in eukaryotic host cells and processes for producing the same and pharmaceutical compositions containing the same.

Abstract: A nucleic acid which can be used to express a polypeptide with interleukin-16 activity in a prokaryotic or eukaryotic host cell, wherein in the region coding for the said polypeptide the said nucleic acid a)corresponds to the DNA sequence of nucleotides 54-1175 from SEQ ID NO:1 or to its complementary strand, b) hybridizes with the DNA of nucleotide sequence 54-785 from SEQ ID NO:1 under stringent conditions, c) hybridizes with the DNA of nucleotide sequence 786-1175 from SEQ ID NO:1 under stringent conditions and at the 5′ end begins with nucleotides 756-785 from SEQ ID NO:1 or a part thereof which codes for part of the sequence of amino acids 235-244 from SEQ ID NO:1 or d) it is a nucleic acid sequence which would hybridize under stringent conditions with the nucleic acid sequences defined by a) or b) without the degeneracy of the genetic code, codes for proteins with improved interleukin-16 activity.

Abstract: An isolated polypeptide which inhibits the replication of retroviruses in peripheral blood lymphocytes and i) is encoded by the DNA sequence shown in SEQ ID NO: 1 or complementary sequences; or ii) is encoded by DNA sequences which are degenerate to those of SEQ ID NO: 1 or its complement, and nucleic acids encoding said polypeptide. The protein is useful for inhibition of viral replication.