Drug – bio-affecting and body treating compositions – Antigen – epitope – or other immunospecific immunoeffector – Virus or component thereof
Reexamination Certificate
1998-04-30
2001-01-09
Park, Hankyel (Department: 1645)
Drug, bio-affecting and body treating compositions
Antigen, epitope, or other immunospecific immunoeffector
Virus or component thereof
C424S188100, C424S199100, C530S388350, C530S389400
Reexamination Certificate
active
06171596
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the use of recombinant proteins to stimulate an immune response in a mammal. Specifically, the present invention describes methods for producing and purifying genetically engineered HIV-1 gp140, 140(prime) and gp120/20 glycoprotein oligomers that can be used as immunogens.
BACKGROUND OF THE INVENTION
The HIV-1 envelope (env) glycoprotein is a structurally complex integral membrane protein that targets the virus to CD4 positive cells and mediates the fusion between the viral envelope and the cellular membrane. This glycoprotein also harbors antigenic determinants that are recognized by neutralizing antibodies.
The two recognized categories of antibodies that are capable of neutralizing HIV-1 infection include: those that recognize determinants in the V3 loop of gp120 and those that block the gp120-CD4 interaction by binding to conserved regions of gp120. Antibodies directed against the V3 loop generally recognize epitopes formed by a short continuous sequence and are usually referred to as conformation-independent. These conformation-independent antibodies can be elicited by immunization with either peptides or denatured env protein subunits. Extensive antigenic variation in the V3 domain of the env protein restricts the neutralizing activity of anti-V3 loop antibodies to closely related strains of HIV-1. Hence, antibodies capable of neutralizing infection by one strain of HIV-1 may not effectively neutralize infection by a different strain of HIV-1.
In contrast, antibodies to epitopes that are sensitive to the conformation of the protein are typically more broadly neutralizing. Antibodies to these conformation-sensitive epitopes are referred to herein as “conformation-dependent” antibodies. Conformation-dependent antibodies that block CD4 binding, for example, recognize conserved, discontinuous, conformational epitopes in gp120. These antibodies are broadly neutralizing and have been shown to comprise a significant fraction of the total neutralization activity present in HIV-1 infected human sera. In addition, there is evidence that neutralizing antibodies may also be directed against conformationally-dependent epitopes on gp120 (Steimer et al.,
Science,
254:105 (1991)).
Newly synthesized gp160 monomers noncovalently associate to form higher order oligomeric structures. The association of two env monomers to form a dimer is the most elemental such structure. A larger structure that is believed to be composed of a dimer of dimers, or four monomers, can also form. The ectodomain of gp41 is required for efficient oligomerization of dimers and tetramers (Earl et al.,
Proc. Natl. Acad. Sci. USA
87:648 (1990); Earl and Moss,
AIDS Res.
9:589-594 (1993)).
Given its antigenic nature, the use of recombinant gp160 or derivatives thereof as immunogens represents an attractive vaccine strategy. However, the attempts that have been made to date in this regard have all suffered one or another deficiency. To the extent that humoral immune responses against various gp160 immunogens have been analyzed, none satisfactorily stimulates the broadly neutralizing antibodies that would be required of an effective HIV-1 vaccine. Hence, there remains a need for a vaccine composition that can stimulate the production of broadly neutralizing antibodies against various strains of HIV-1.
SUMMARY OF THE INVENTION
In a first aspect of the invention, there is provided a composition for stimulating an anti-HIV-1 env immune response in a mammal. The composition includes an oligomer of a secreted C-terminally truncated form of an HIV-1 gp160 and a pharmaceutically acceptable carrier. The secreted C-terminally truncated form of an HIV-1 gp160 includes a gp120-gp41 proteolytic processing site. According to one embodiment the HIV-1 gp160 is found in a laboratory-adapted strain of HIV-1, such as BH8. According to another embodiment the HIV-1 gp160 is found in a primary isolate of HIV-1, such as HIV-1 89.6 or HIV-1 CM235. When the secreted C-terminally truncated form of the HIV-1 gp160 includes a gp120-gp41 proteolytic processing site, the pharmaceutically acceptable carrier can include a saline solution, and additionally may include an adjuvant. According to yet another embodiment of the invention, the secreted C-terminally truncated form of the HIV-1 gp160 can include the entire amino acid sequence of gp120 of the HIV-1.
In a second aspect of the invention, there is provided another composition for stimulating an anti-HIV-1 env immune response in a mammal. This composition includes an oligomeric gp120/20, which is a proteolytically cleaved form of a secreted C-terminally truncated form of an HIV-1 gp160, and a pharmaceutically acceptable carrier. In one embodiment the HIV-1 gp160 of the composition is found in a primary isolate of HIV-1, and the oligomeric gp120/20 has a molecular weight of at least 200 kDa.
In a third aspect of the invention, there is provided a method of stimulating the formation of neutralizing antibodies against conformational epitopes of HIV-1 env proteins in a mammal. This method includes the steps of first identifying a mammal at risk of contracting an HIV infection; and then administering to the mammal a composition which includes an oligomer of gp140(prime) and a pharmaceutically acceptable carrier, wherein the gp140(prime) is a C-terminally truncated form of an HIV-1 gp160, and the HIV-1 gp160 has a gp120-gp41 proteolytic processing site. According to one embodiment of the method, the composition is administered intramuscularly and can be administered intramuscularly a plurality of times. According to another embodiment, the HIV-1 gp160 is found in a laboratory-adapted strain of HIV-1, such as HIV-1 BH8. According to still another embodiment of the invention, the HIV-1 gp160 is found in a primary isolate of HIV-1, such as HIV-1 89.6 or HIV-1 CM235. According to yet another embodiment, the C-terminally truncated form of the HIV-1 gp160 includes the entire sequence of a mature gp120 that does not include a signal peptide.
In a fourth aspect of the invention, there is provided a recombinant oligomeric gp140.
In a fifth aspect of the invention, there is provided a recombinant oligomeric gp140(prime).
In a sixth aspect of the invention, there is provided a recombinant oligomeric gp120/20.
In a seventh aspect of the invention, there is provided a recombinant oligomeric gp140 or gp140(prime) having been produced by a two-step purification process.
In an eighth aspect of the invention, there is provided a vaccine which includes oligomeric gp140, gp140(prime) or gp120/20.
In a ninth aspect of the invention, there is provided a method of preventing HIV infection in a subject. This method includes the steps of administering a vaccine which includes oligomeric gp140, gp140(prime) or gp120/20 in an amount sufficient to prevent HIV infection.
In a tenth aspect of the invention, there is provided the recombinant viral construct vPE12B.
In an eleventh aspect of the invention, there is provided the plasmid construct pPE12B.
In a twelfth aspect of the invention, there is provided the recombinant viral construct vCB-14.
In a thirteenth aspect of the invention, there is provided the plasmid construct pCB-14.
REFERENCES:
patent: 4725669 (1988-02-01), Essex et al.
patent: 6039957 (2000-03-01), Earl et al.
patent: 9206113 (1992-04-01), None
Folding, Interaction with GRP78-BiP, Assembly and Transport of the Human Immunodeficiency Virus Type 1 Envelope Protein, Earl, Et al., Journal of Virology, Apr. 1991, pp. 2047-2055.
Multimeric CD4 Binding Exhibited by Human and Simian Immunodeficiency Virus Envelope Protein Dimers, Earl, et al., Journal of Virology, Sep. 1992, pp. 5610-5614.
Native Oligomeric Human Immunodeficiency Virus Type 1 Envelope Glycoprotein Elicits Diverse Monoclonal Antibody Reactivities, Earl, et al., Journal of Virology, May 1994, pp. 3015-3026.
Antigenic implications of human immunodeficiency virus type 1 envelope quaternary structure: Oligomer-specific and -sensitive monoclonal antibodies, Earl, et al., Proc. Natl. Acad. Sci. USA v
Broder Christopher C.
Doms Robert W.
Earl Patricia L.
Moss Bernard
Knobbe Martens Olson & Bear LLP
Park Hankyel
The United States of America as represented by the Department of
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