Modified Viral Particles with Immunogenic Properties and Reduced Lipid Content Useful for Treating and Preventing Infectious Diseases

Abstract

The present invention relates to a method for reducing the occurrence and severity of infectious diseases, especially infectious diseases in which lipid-containing infectious viral organisms are found in biological fluids, such as blood. The present invention employs solvents useful for extracting lipids from the lipid-containing infectious viral organism thereby creating modified viral particles with reduced infectivity and enhanced antigenicity. The present invention provides vaccine compositions, comprising these modified viral particles with reduced infectivity and enhanced antigenicity, optionally combined with a pharmaceutically acceptable carrier or an immunostimulant. The vaccine composition is administered to a patient to provide protection against the lipid-containing infectious viral organism. The vaccine compositions of the present invention include combination vaccines of modified viral particles obtained from one or more strains of a virus and / or one or more types of virus.

Description

RELATED APPLICATIONS[0001]This application is a continuation-in-part of U.S. non-provisional patent application Ser. No. 10 / 601,656 filed Jun. 20, 2003, which is a continuation-in-part of U.S. non-provisional patent application Ser. No. 10 / 311,679 filed Dec. 18, 2002, which is a U.S. national phase from PCT patent application number PCT / IB11 / 01099 filed Jun. 21, 2001, which claims the benefit of Australian patent application PQ8469 filed Jun. 29, 2000 and PCT patent application number PCT / AU00 / 01603 filed Dec. 28, 2000. U.S. non-provisional patent application Ser. No. 10 / 311,679 claims the benefit of U.S. provisional patent application Ser. No. 60 / 390,066 filed Jun. 20, 2002. The present application also claims the benefit of U.S. provisional patent application Ser. No. 60 / 491,928 filed Aug. 1, 2003, 60 / 533,542 filed Dec. 31, 2003, and 60 / 542,947 filed Feb. 9, 2004.FIELD OF THE INVENTION[0002]The present invention relates to a delipidation method employing a solvent system useful fo...

AI Technical Summary

Benefits of technology

[0025]The present invention solves the problems described above by providing a simple, effective and efficient method for treating and preventing viral infection. The method of the present invention affects the lipid envelope of a virus by utilizing an efficient solvent system, which does not denature or destroy the virus. The present invention employs an optimal solvent and energy system to create, via delipidation, a non-synthetic, host-derived or non host-derived modified viral particle that has its lipid envelope at least partially removed, generating a positive immunologic response when administered to a patient, thereby providing that patient with some degree of protection against the virus. It is believed that these modified viral particles have at least one antigen exposed that was not exposed prior to the delipidation process.

[0026]The present invention is also effective in producing an autologous, patient-specific therapeutic vaccine against the virus, by treating a biological fluid containing the virus such that the virus is present in a modified form, with reduced infectivity, and such that an immune response is initiated upon reintroduction of the fluid with reduced lipid content into the patient. This autologous method ensures that patient specific antigens, for example patient specific viral antigens, are introduced into the same patient from which they were obtained to induce an immune response. This is an important feature since a patient's physiology may modify the antigens present in an infectious organism such as a virus. To create the vaccine, a biological fluid (for example, blood) is removed from the patient, the plasma is separated from the blood and treated to reduce the lipid content of the virus in the plasma using an optimal solvent system. A lipid-containing virus, treated in this manner in order to reduce its infectivity and create a modified viral particle with reduced lipid content is administered to a patient, such as an animal or a human, optionally together with a pharmaceutically acceptable carrier, in order to initiate an immune response in the animal or human and create antibodies that bind the exposed epitopes of the modified viral particle. Adjuvants may also be administered with the modified viral particle in the pharmaceutically acceptable carrier or separately.

[0027]The present method is also employed to produce non-autologous vaccines, wherein biological fluids with lipid containing viruses from at least one animal or human are treated to produce a modified viral particle for administration into a different (non-autologous) animal or human. The present invention is also effective in producing an non-autologous, vaccine against the virus, by treating a biological fluid such as plasma obtained from an animal or a human with the present method to reduce lipid levels in the fluid and in the virus within the fluid. Such treated fluid with reduced lipid levels and containing modified virus with reduced lipid levels may be introduced into another animal or human which was not the source of the treated biological fluid. This non-autologous method is employed to vaccinate a recipient animal or human against one or more infectious organisms such as viruses. Biological fluids may be used from animals or humans infected with one or more infectious organisms such as viruses, and treated with the present methods to produce a vaccine for administration to a recipient animal or human. Alternatively, or in addition, various stock supplies of virus may be added to a biological fluid before treating the fluid with the method of the present invention to create a vaccine.

Problems solved by technology

Viruses, of varied etiology, affect billions of animals and humans each year and inflict an enormous economic burden on society.

Viruses affect animals and humans causing extreme suffering, morbidity, and mortality.

The immune system is forced to produce the “compromise”, ineffective antibodies which do not destroy the viral particles, allowing them to proliferate and slowly cause severe damage to the body, while destroying host cells.

The high mutation rate of the virus, especially in the case of HIV, is a major difficulty with existing treatments because the various strains become resistant to anti-viral drug therapy.

Furthermore, anti-viral drug therapy treatment may cause the evolution of resistant strains of the virus.

Other drawbacks to drug therapies are the undesirable side effects and patient compliance requirements.

Such individuals require even more aggressive and expensive drug regimens to counteract disease progression, which in turn cause greater side effects and a greater likelihood of multiple drug resistance.

Strict adherence to HAART regimen remains a major hurdle, and lapses in compliance lead to bursts of viral replication, and selection of drug resistant strains.

Additionally, long-term use of HAART is associated with side effects such as lipodystrophies, altered glucose metabolism and elevated cholesterol and triglycerides in plasma.

The current methods of vaccination do have drawbacks, making them less than optimally desirable for immunizing individuals against particular pathogens, especially HIV.

One explanation offered in the prior art is that the antigens of these microorganisms change constantly so the antibodies produced in response to a particular antigen are no longer effective when the antigen mutates.

Although antigenic variation has been addressed via the attempted use of combination drugs or antigens, no prior art vaccine has succeeded in addressing chronic infections such as HIV.

Viral inactivation does present problems since inactivation of a virus does not provide a protective immune response against viral infection.

In addition, it is largely geared towards denaturing viral proteins, thereby destroying the structure of the viral particle.

In sum, prior art methods have largely focused on destroying, yet not suitably modifying, viral particles to produce an immune response.

In addition to dissolving the lipid envelope of the virus, the high organic solvent concentrations cause cell death and damage to the antigens.

Essentially, this method results in a “chemical kill” of the cell.

Although treating the virus with glutaraldehyde effectively delipidates the virus, it also destroys the core.

Destruction of the core is not desirable for producing a modified viral particle useful for inducing an immune response in a recipient.

Chloroform, however, denatures many plasma proteins and is not suitable for use with biological fluids, which will be reintroduced into the animal or human.

These functions are essential to life and thus damage to these proteins may have an adverse effect on a patient's health, possibly leading to death.

Many of these methods, especially those involving detergents, require tedious procedures to ensure removal of the detergent before reintroduction of the treated plasma sample into the animal or human.

Further, many of the methods described in the prior art involve extensive exposure to elevated temperature in order to kill free virus and infected cells.

Elevated temperatures have deleterious effects on the proteins contained in biological fluids, such as plasma.

Attenuated vaccines (less infective and not inactivated), however, pose several problems.

First, it is difficult to ascertain when the attenuated vaccine is no longer pathogenic.

The risk of viral infection from the vaccine is too great to properly test for effective attenuation.

In addition, attenuated vaccines carry the risk of reverting into a virulent form of the pathogen.

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