A vaccine is a biological substance introduced into the body to build-up immunity against an invading germ like bacteria or viruses. A vaccine works by stimulating the production of antibodies against the invading micro-organism, stimulating the production of certain special "military" cells called CTL (Cytotoxic T Lymphocytes) that search and destroy body-cells that contain the invading organism, or a combination of both of the actions. The first method is useful primarily against bacteria and the second primarily against viruses.
Specifically, a therapeutic vaccine is one that is given to a patient AFTER being exposed to an invading micro-organism. In contrast, a "prophylactic" vaccine is given BEFORE exposure to prevent the micro-organism from invading in the first place. One example of a therapeutic vaccine is the one currently used for the treatment of rabies. Therapeutic vaccines are useful only when the incubation period (the time between being infected and the onset of symptoms) of the illness is long enough that defense mechanisms can be established before death occurs. In HIV, the incubation period is 10 or more years allowing enough time for the immune system to be strengthened by the vaccine before death. This "therapeutic" use is different from the more common preventive (prophylactic) use of vaccines in childhood immunizations for diseases such as diphtheria, whooping cough, and measles.
A live vaccine contains a weakened version of a live micro-organism (bacteria or virus) against which one desires to build-up protective immunity. The oral vaccine against polio (Sabin) or the rabies vaccine belong to this category. Other vaccines use only a portion of the invading micro-organism's proteins or dead micro-organisms as in the Salk vaccine. Live vaccines build-up "military cells" (CTL) that, once activated, go on search-and-destroy missions killing the invading micro-organisms. Dead vaccines usually only produce antibodies against the invading micro-organism but are unable to form "military cells". Your body is capable of making antibodies against a portion of a foreign virus or bacterium without actually being infected.
A recombinant vaccine is created by genetically altering the invading virus. The purpose of genetically altering the virus is to weaken it so that it can boost immunity without causing death and disease. In the case of recombinant HIV, the vaccine contains everything from a live HIV strain except the nef gene. Previously, other methods were used to make vaccines in which the micro-organisms were weakened by methods such as heat, radiation and chemicals. These methods are not useful in making a live anti-HIV vaccine because the virus is extremely fragile and dies when conventional weakening methods are used.
Yes. All the live vaccines such as those for small pox, rabies, rubella, measles and polio work by making specific "military cells" that search, identify and destroy any invading virus-bearing cells and thus not allowing the infection to take hold or eliminate if it is established. Contre Vir™ is not at all unique from the perspective of how these vaccines work.
HIV sufferers die because the virus populates unhindered, killing an immune system that is essential for survival. Since it attacks the immune system, the patients die from a variety of other infections to which they are rendered defenseless.
The body tries. Most patients have very high levels of circulating antibodies against HIV. However, these antibodies don't do much good because the virus is hidden inside cells where the antibodies cannot reach. What fails in HIV infection is a concerted attack of "military cells" (CTLs) against any cell harboring HIV. In order to have such a strong attack, the infected cells need to send a minimum of TWO signals to the "military cells". The first signal is the appearance of foreign proteins on the surface of the invaded cell that are recognized by specific "military cells" to attack. The second signal is a specific chemical signal sent by means of certain specific chemicals some of which are called "lymphokines". A protein generated by HIV called "Nef" has been shown to prevent a specific modification in the first signal AND interfere with several lymphokines required for the second signal. Thus, HIV blocks the signaling successfully and renders the "military cells" ineffective. This blocking or cloaking mechanism is contained on a specific gene of the HIV called nef which produces the Nef protein.
ImmunoScience, Inc., Inc. manufactures Contre Vir™ by genetically altering HIV's nef gene (the cloaking or blocking gene) thus making a new, weakened version of the virus. This version of the virus is unable to stop the production, recruitment and attack of the "military cells" (CTLs). Thus, it cannot harm the human in a similar way as a heat-treated or radiation treated live virus vaccine would.
Contre Vir™, which is essentially a live but weakened HIV virus, is administered to a patient suffering from HIV infection. Contre Vir™ invades the patient's body just as real HIV does. However, unlike the real HIV, Contre Vir™ will not interfere with production, recruitment and attack of "military cells". The "military cells" will now do their designated job and start "search and destroy" missions throughout the body to kill any cell harboring HIV. Since there is no difference between Contre Vir™ and the "real" HIV in terms of the proteins seen on the surface of the cell, activated "military cells" cannot tell the difference between cells containing Contre Vir™ and cells containing the "real" HIV, thus killing them all.
It's a situation where similarities and dissimilarities are used to best advantage. The dissimilarity between the two viruses allows the "military cells" to function properly whereas the similarity makes both of them identifiable to the "military cells" without cloaking.
The current research protocol consists of two injections of Contre Vir™- a month apart. Further research may require modification of this protocol.
Most patients are expected to show substantial improvement in their immune system within 14-16 weeks after the first injection. This period will be better defined after the first larger scale clinical trial.
In the company's opinion, it has the potential to be a cure. Since the "military cells" have a long memory, and access to every part of the body, it is postulated that they will destroy every cell harboring HIV in a finite period of time, eliminating the virus completely from the body. However, many cells in the body, particulary in the brain, will carry dormant copies of the viral DNA permanently and in some scientists' view, HIV is incurable for that reason.
Yes. However, because testing for HIV involves detection of antibodies, these patients will be 'HIV Positve" even though they are disease free because of the presence of these antibodies. This is similar to one having antibodies to a strep infection long after it is cured by antibiotics.
The results may vary, however, it is estimated that within 18-24 months after the first injection, HIV shall be eliminated from the body. This period will be better defined after the first larger scale clinical trial.
Not likely. One expects the immunity created by Contre Vir™ to be life-long and no repeat infection is likely from all the known sub-types of the HIV virus.
The proteins that the "military" cells see on the surface of the infected cells are from a "conserved" i.e., non-changing part of the virus called Gag proteins. Since these proteins do not change frequently like the Env (envelope) proteins, Contre Vir™ should maintain its effectiveness infinitely and across almost the entire spectrum of mutant strains.
The drugs used in the treatment of HIV do not kill the "blue-prints" of HIV (pro-viral DNA). They only stop production of the virus from these "blue-prints". Given over a period of time, the cells containing the "blue-prints" die and are replaced with healthy cells. For example, the blood cells , mucosal and lymphoid cells are replaced in about a year and eliminate the virus "blue-prints" harboring within them. HOWEVER, the "blue-prints" also exist in some brain cells called "microglia" and these cells are in the body for life. They do not die out. These "blue-prints" present in the brain are fully capable of generating large quantities of the virus and re-invading the whole body as soon as the drugs are stopped or as soon as the virus becomes resistant to the effect of the drugs.
Once HIV has been eliminated from the body, the patients will not be able to infect others. However, during early stages of treatment, they will be able to transmit HIV.
Research is still not complete. However, it is not likely that introduction of additional HIV in one already infected will pose any substantial danger and potential for side-effects. The patients in the pilot studies reported no side effects.
This is a possibility. Contre Vir™ can indeed be used as a "prophylactic" vaccine to immunize the body before the infection. However, the use of such a vaccine in healthy subjects raises serious ethical questions and thus it would be impossible to do such a research. Furthermore, since HIV can be more easily prevented by avoiding high-risk behavior known to be associated with the transmission of HIV, abstaining from such behavior continues to be the best means of prevention. Contre-Vir™ may eventually have application as a prophylactic vaccine for high-risk individuals such as chronic recipients of blood products, prison populations and for commercial sex workers or habitual IV drug abusers.
Once HIV is eliminated from the body, the patients are not be able to infect others. However, there is research on this issue has not been completed.
Patent applications were made with a priority date of December 24, 1994 and have been actively pursued in the United States, Canada, Japan, Brazil, all countries in Europe and several more countries. In July 2000, an Australian patent was granted. US Patents were granted to Contre Vir™ in 2004, 2009 and 2012. A Canadian patent was awarded in July 2008 and an EU national phase patents was awarded in August 2008. A Japanese patent was granted in 2011.