Title:  Prophylaxis and therapy of acquired immunodeficiency syndrome

United States Patent:  6,265,539

Assignee:  The University of Texas System The Board of Regents (Austine, TX)

Filed:  February 13, 1992

An active peptide consisting essentially of 7 to about 30 residue and having a sequence that corresponds to a conserved domain of an HIV protein is disclosed, as is a multimer containing that peptide, an aqueous composition containing the multimer and methods of using and making the same. The aqueous composition containing an immunologically effective amount of an active peptide multimer, when introduced into an immunocompetent host animal in an immunologically effective amount, is capable of inducing cellular immunity against the native HIV protein to which the active peptide of the multimer corresponds in sequence, but is not capable of inducing production of antibodies that immunoreact with that native HIV protein.

SUMMARY OF THE INVENTION

The present invention contemplates a peptide, a peptide multimer, an aqueous composition containing the peptide multimer and a method of using the composition.

A peptide of the invention contains 7 to about 30 amino acid residues, and has a sequence that corresponds to a conserved domain of an HIV protein such as the gp160 envelope and core proteins. Preferred peptides have a sequence that corresponds to a portion of a conserved domain selected from the group consisting of the first, second, third and fifth conserved domains of the gp160 molecule.

A peptide of the invention is generally used as a portion of a peptide multimer. Two specific classes of peptide multimers are disclosed. In one class, the amino-terminal residue of a peptide is peptide-bonded to a spacer peptide that contains an amino-terminal lysyl residue and one to about five amino acid residues such as glycyl residues to form a composite polypeptide. Those added residues of the spacer peptide do not interfere with the immunizing capacity of the multimer, nor with its capacity to form surfactant-like micelles in aqueous compositions. The alpha- and epsilon-amino groups of the amino-terminal lysyl residue are amidified with a C₁₂ -C₁₈ fatty acid such as palmitic acid to form the reaction product that is used. The di-amide so formed forms surfactant-like micellular multimers in an aqueous composition.

A second class of multimer is a polymer having a before-described peptide as a repeating unit. Here, each peptide is synthesized to contain a cysteine (Cys) residue at each of its amino- and carboxy-termini. The resulting di-cysteine-terminated (di-Cys) peptide is then oxidized to polymerize the di-Cys peptide monomers into a polymer or cyclic peptide multimer in which the peptide repeating units are linked by stine (oxidized cysteine) residues.

A peptide multimer of either class can contain one or a plurality of different peptide sequences. A before-described peptide of a multimer is an "active" peptide in that when used in a composition discussed below, the multimer can induce cell mediated immunity such as production of cytotoxic T cells. A multimer can also include an inactive peptide, for example to assist in dispersing the multimer in the aqueous medium. The lysyl-containing peptide spacer discussed before can be viewed as such an inactive peptide.

The peptide multimer is utilized in an aqueous composition (inoculum). That composition contains water having a before-described multimer dispersed therein. The composition, when used to immunize an immunocompetent host animal such as a mouse, has the capacity of inducing cell mediated immunity such as cytotoxic T cell activation to the native HIV protein corresponding in sequence to that of an active peptide of the multimer, but does not substantially induce production of antibodies that immunoreact with that corresponding native HIV protein. The composition thus contains an immunizing effective amount of a before-discussed multimeric peptide.

In one method aspect of the invention, an immunizing amount of an above composition containing an immunizing effective amount of an active peptide multimer is introduced into (administered to) an animal host such as a mouse or human to induce cellular immunity such as T cell immunity to a preselected native HIV protein without production of antibodies that immunoreact with that preselected native HIV protein. The preselected HIV protein is the HIV protein to which the active peptide corresponds in sequence. The immunized animal is then maintained to permit the immunity to be induced. This immunization can be repeated or boosted as desired.

Another method aspect of this invention is a method of killing target cells that exhibit an HIV protein or a portion of an HIV protein on the cell surfaces. Here, target cells that exhibit an HIV protein or a portion of an HIV protein on their cell surfaces such as HIV-infected T cells or leukocytes that are artificially made to express cell surface HIV proteins are contacted with a killing effective amount of cytotoxic T cells that have been activated using a before-described composition. The cell surface-exhibited HIV protein and the HIV protein to which an active peptide of the multimer corresponds in sequence are the same proteins, since the core protein and the two processed portions of the gp160 protein (the gp120 and gp41 envelope proteins) are the proteins normally found on HIV-infected cell surfaces. That contact is maintained for a time period sufficient for the cytotoxic T cells to kill the target cells. This method can be carried out in vitro or in viva in the body of a host animal.

Claim 1 of 18 Claims

What is claimed is:

1. An isolated peptide of from 7 to about 30 acid residues comprising one or more of the following amino acid residues of gp120 within its structure: AA^39-51 ; AA^45-55 ; AA^48-61 ; AA^72-82 ; AA^81-92 ; AA^92-102 ; AA^105-116 ; AA^118-130 ; AA^204-216 ; AA^215-228 ; AA^240-252 ; AA^586-598 ; AA^519-543 ; or AA^417-435.

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