Purposeful use of DNA - DNA Vaccines

In this research you will find them ADMITTING the dangers of vaccines.........

"The advent of DNA-based vaccination provides a relatively safe way of developing both humoral and cellular immune responses while allowing for the production of artificial immunogens and co-expression of other factors that can affect and enhance immune responses e.g. cytokines2." (vaccines we have have problems as we have talked about - one is that they don't stimulate both aspects of immune system - humoral & cellular; another is that they for sure don't work against intracellular pathogens.....Sheri)

So they are trying to find a way around these problems and again messing with the fabric of life

Sheri


"At this point in time, the method by which DNA vaccines stimulate the immune system is not clearly understood, "

"At this time, these dangers and other potential pit-falls are not clearly understood and must be studied further."

"There Is Always Danger
Although there appears to be great potential and many benefits to the process of DNA vaccination, the dangers must not be ignored. Current concerns include the potential for plasmid DNA to integrate into the host genome, causing untold changes in host cell development. It is also a possibility that the plasmid DNA could affect the expression of host genes that control cell growth, without any genetic integration. There are also fears that the use of genetic material that encodes a specific antigen may lead to tolerance to that antigen over time14."

http://cwis.livjm.ac.uk/bms/AMH%20pa...vol2/moore.doc

DNA - A New Bullet for the Vaccination Gun

By
Jonathan Moore

Deoxyribonucleic acid (DNA) contains all of the genetic information required for life. Its importance is immeasurable. Does this miracle molecule hold the key to the cure for much of the disease that takes millions of lives in the 21st century?

Vaccine Wall

Edward Jenner - a name known throughout the scientific world for the development of the first successful human vaccine, approximately 200 years ago. He was able to demonstrate that inoculation of a boy with cow pox virus protected him against small pox infection. Since this discovery, the development of vaccines against modern disease has been a major area of scientific research. Much success has been achieved and life-threatening diseases, such as small pox, have been eradicated.

Unfortunately, vaccine development has come to a wall that is proving to be difficult to climb. There are no consistently effective vaccines available against diseases such as tuberculosis, human immunodeficiency virus (HIV) and other infections caused by intracellular pathogens3. Many of the diseases that plague mankind at this time, such as HIV and malaria15, require both humoral (antibody) and cellular immune responses for defence and protection and modern vaccines do not live up to the task.

One of the latest and most promising approaches for tackling this problem is DNA vaccination. There is mounting evidence from numerous studies that the injection of free DNA (naked DNA) stimulates long-term immune responses to the protein antigen encoded for by the DNA1. The advent of DNA-based vaccination provides a relatively safe way of developing both humoral and cellular immune responses while allowing for the production of artificial immunogens and co-expression of other factors that can affect and enhance immune responses e.g. cytokines2.

The Power of Plasmids

The term "DNA vaccination" currently refers to the induction of immune responses to an antigen expressed in vivo subsequent to the introduction of purified plasmid DNA encoding the genetic sequence of the antigen3. If the introduction of plasmid DNA is efficient and safe, DNA-based vaccines may provide an attractive alternative to classical methods, such as the use of live or attenuated (weakened) pathogens.

Plasmids are an essential requirement of DNA vaccines. In nature, plasmids are autonomously replicating entities that can be found in essentially all bacterial species and contain genetic information coding for RNA molecules and protein. They are normally circular, although linear forms have also been found. They vary widely in size from 1 kilobase (kb) to 200kb, and larger "megaplasmids" of up to 1000kb have been identified. Plasmids replicate as the cell grows and equal numbers are normally distributed to the daughter cells upon division. However, plasmids do not code for functions that are essential to bacterial life4.

A plasmid vector is an autonomously replicating DNA molecule into which foreign DNA can be inserted. The foreign DNA will be replicated along with the rest of the vector following introduction into a cell4. In the case of DNA vaccination, the foreign DNA codes for the antigen to which an immune response is required.

How Do DNA Vaccines Stimulate The Immune System?

For a rational vaccine design, an understanding of the immunological response of host to infection is essential, as the vaccine action should mimic that of the invading pathogen. At this point in time, the method by which DNA vaccines stimulate the immune system is not clearly understood, although recent discoveries have shown that plasmids appear to make their way into professional antigen presenting cells (APC) such as dendritic cells, which then display antigen on their surface alongside the other critical molecules required for effective stimulation of T-cell populations3. It seems that direct inoculation of appropriate plasmid DNA results in the in vivo synthesis of antigen in patterns that are identical, in most cases, to those found during normal infection3.

Recent research has described DNA vaccines in mice against several diseases such as hepatitis D5 and dengue virus6. The vast majority of experimentation in this area takes place using mouse models. Current DNA vaccines have been shown to be less effective in larger animals, although monkeys have been protected from measles, dengue virus and HIV antigens7. The science of DNA vaccination is making steady progress at every turn, and so the future looks bright. However, in order to use DNA successfully in this manner, there are many factors that must be studied and understood.

Factors Affecting the Efficacy of DNA Vaccines

The immune response induced upon DNA vaccination is influenced by the site and mode of injection. Various routes have been tested including intramuscular, intradermal and mucosal (for example, oral and vaginal) delivery of DNA7.

For reasons of stability for administration, DNA can also be combined with different synthetic or biological carriers such as gold particles, liposomes and attenuated organisms, such as Salmonella7.

Probably the most widely used method for the introduction of DNA is needle injection into muscle tissue (intramuscular), especially when dealing with antiviral DNA vaccines. This method was first used for the generation of antibodies against a viral protein involved in influenza8. In animal models, it has been shown to be less effective in larger animals, probably due to the increased muscle thickness and complexity9. As with all DNA vaccination procedures, the injection conditions, such as speed, angle and volume, can have a large influence on efficiency and immune response7, 10. To further enhance immune response, it has been reported that treating muscle tissue with toxic agents such as bupivacaine (a local anesthetic) is successful. However, there may be severe side affects in some animals7.

When an intradermal method of injection is used for DNA vaccines, only a small number of cells are affected. This is a fact shared with intramuscular injection11. However, it has been shown that intradermal injection can provide greater immune responses with an example being the administration of influenza encoding plasmids7. A natural inhibitor, known as lipocortin, is found in the skin and this restrains inflammatory responses that would lead to the eventual destruction of those cells affected by the vaccine. This may allow APCs to survive for a longer period of time and enable skin cells to produce and present antigen continuously7. This situation may lead to continuous activation of the immune system and may explain the success of intradermal delivery11.

Mucosal administration of DNA vaccines seems to be important for protection against pathogens that invade their host via mucosal surfaces7. Several strategies have been defined, including oral, intranasal and genital tract inoculations7. In recent studies, mucosal vaccination required five times less DNA that intradermal in order to induce the same level of protection against challenge from rotavirus. This indicated that mucosal administration is superior to intradermal using the same vaccine dose12.

Viral Systems of DNA Vaccine Delivery

In order to enhance the reaction of the immune system to DNA vaccines, alphavirus genomes derived from Semliki forest virus (amongst others) have been used to develop highly efficient viral expression vectors. Plasmid DNA is packaged inside of alphavirus particles that are then injected into the test animal. High level production of antigen is achieved as the alphavirus replicates within host cells and this antigen stimulates the immune system. This method has been shown to gain a significant increase in humoral and cellular immune responses when compared to conventional naked DNA vaccination13. The use of viral systems for DNA vaccine delivery is a highly active area of research at this time.

The Use of Adjuvants

A common inclusion with most DNA vaccines is that of an adjuvant. An adjuvant is defined as an immunological agent that is designed to enhance the immune response. Complete Freund's Adjuvant (CFA), an oil-in-water emulsion containing mycobacterial cell wall components, is regarded as an effective means of enhancing antibody response to injected immunogens. The effect is a result of sustained release of antigen from the oily deposit and stimulation of a local immune response. Immunostimulatory CpG motifs are sections of genetic information, common in bacterial DNA but rare in mammalian DNA, which are also commonly used as adjuvants16. CpG DNA can activate many immune cells including APCs and the cellular response to CpG is mediated by a Toll-like receptor that can distinguish between self and foreign DNA.

Genetic adjuvants are also used in modern DNA vaccines. This method requires the inclusion of genetic information within a plasmid that codes for a factor that will stimulate and enhance the immune response, such as a cytokine7.

There Is Always Danger

Although there appears to be great potential and many benefits to the process of DNA vaccination, the dangers must not be ignored. Current concerns include the potential for plasmid DNA to integrate into the host genome, causing untold changes in host cell development. It is also a possibility that the plasmid DNA could affect the expression of host genes that control cell growth, without any genetic integration. There are also fears that the use of genetic material that encodes a specific antigen may lead to tolerance to that antigen over time14.

At this time, these dangers and other potential pit-falls are not clearly understood and must be studied further.

The Next Step

It is clear that greater understanding of all aspects of DNA vaccination must be achieved before we can hope to gain the fruit from the DNA vaccine tree. Distribution, cellular uptake and expression of the vaccines must be understood in order to make limitations clear3. For each individual vaccine, it is important to determine the optimal regime for use, in terms of vaccine dose, timing of boosters and delivery routes3. Also, promising DNA vaccines should be tested in animal models that closely mimic the human disease and efforts should be made to reduce the cost of DNA vaccination, which is far too high at present3. In order to make the process commercially viable for use in humans, the expense must be lowered.

References

1. Montgomery, DL, Huygen, K, Yauman, AM, et al
Induction of humoral and cellular immune responses by vaccination with Mycobacterium tuberculosis antigen 85 DNA.
Cell. Mol. Biol. (1997); 43: 285-92

2. Ulmer, JB, Deck RR, Dewitt, CM, Donnhly, JI, Liu, MA
Generation of MHC-1 restricted cytotoxic T lymphocytes by expression of a vital protein in muscle cells: antigen presentation by non-muscle cells.
Immunology (1996); 89: 50-63

3. Sharma, AK and Khuller, GK
DNA vaccines: Future strategies and relevance to intracellular pathogens.
Immunology and Cell Biology (2001) 79, 537-546

4. Schleef, M (Ed.)
Plasmids for therapy and vaccination.
Wiley Europe (2001)

5. Huang, YH, Wu, JC, Tao, MH, Syu, WJ et al
DNA-based immunization produces Th1 immune responses to hepatitis delta virus in a mouse model.
Hepatology (2000); 32: 104-110

6. Raviprakash, K, Kochel, TJ, Ewing, D et al
Immunogenicity of dengue virus type 1 DNA vaccines expressing truncated and full length envelope protein.
Vaccine (2000); 18: 2426-2434

7. Schultz, J, Dollenmaier, G, Molling, K
Update on antiviral DNA vaccine research (1998-2000)
Intervirology (2000); 43: 197-217

8. Ulmer, JB, Donnelly, JJ, Parker, SE et al
Heterologous protection against influenza by injection of DNA encoding a viral protein.
Science (1993); 259: 1745-1749

9. Jiao, S, Williams, P, Berg, RK et al
Direct gene transfer into non-human primate myofibers in vivo.
Hum. Gene Ther. (1992); 3: 21-33

10. Rolland, AP, Mumper, RJ
Recent advances in polymer delivery systems.
Adv. Drug Deliv. Rev. (1998); 30: 151-159

11. Raz, E, Carson, DA, Parker, SE et al
Intradermal gene immunization: The possible role of DNA uptake in the induction of cellular immunity to viruses.
Proc. Natl. Acad. Sci. USA (1994); 91: 9519-9523

12. Chen, SC, Fynan, EF, Greenberg, HB et al
Immunity obtained by gene-gun inoculation of a rotavirus DNA vaccine to the abdominal epidermis of anorectal epithelium.
Vaccine (1999); 17: 3171-3176

13. Berglund, P, Smerdou, C, Fleeton, MN et al
Enhancing immune responses using suicidal DNA vaccines.
Nat. Biotechnology (1998); 190: 191-195

14.
http://homepages.ucl.ac.uk/mob5542v/...tion/index.htm
Accessed - 11/3/2003

15.
Vince, G.
Malaria vaccine trials underway in Gambia.
http://www.newscientist.com 19/8/2002
Accessed - 29/3/2003

P.T.O.

16.
Westphal, S.P.
Immune system booster could combat bioweapons.
http://www.newscientist.com 7/11/2001
Accessed - 29/3/2003

Thank you and goodnight…

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http://www.fact-index.com/d/dn/dna_vaccination.html

"Most people have been immunized against some diseases. This has lead to a decrease of infections with these diseases in the industry nations and worldwide. Naturally-occurring cases of smallpox have been totally eliminated. But even though the methods of vaccination have been much improved over the last decades, they still hold several disadvantages.

Some are based on damaged or destroyed pathogens. If the damage was not completely successful, the vaccination itself can cause the disease it was intended to prevent. Even a "safe" vaccine can cause severe side-effects. Also, you can only be immunized against a single or a few variants of a disease at the same time. Many of today's vaccines have to be constantly cooled, making transport and storage hard and expensive, especially in warm regions of the earth."

Sheri Nakken, R.N., MA, Classical Homeopath
http://www.nccn.net/~wwithin/homeo.htm

As long as there is some pharmaceutical giant ready to make a profit out of vaccines . There will always be money to finance the the "" scientific"" research to back up the use of this method of limiting the world population.