A T and B cell prophylactic and therapeutic HIV vaccine
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HIV-v
- HIV-v is a T and B cell vaccine against the conserved regions of the HIV virus
- The conserved regions are all in the internal proteins
- The is the first vaccine to form an antibody response to a conserved internal protein
- HIV-v is capable of being a prophylactic (prevents disease) or a therapeutic (treats disease) vaccine
- HIV-v is made up of part-proteins from NEF, REV, VIF and VPR non-capsid HIV proteins
- HIV-v is synthetically manufactured making it inexpensive to produce and able to be made in large quantities
- HIV-v has obtained patent protection in major countries globally
Phase Ib/II Human Trials
- A therapeutic trial of 55 HIV patients at 6 centres in the UK has shown a 90% reduction in the viral load of vaccinated patients compared with natural disease progression
- A sub group of patients have shown a 90% reduction in their viral load compared with their level prior to trial commencement
- CD4 immune cells in this sub group increased compared with their levels prior to the trial. All others levels of CD4 remained the same
- HIV-v had no safety issues associated with it and was well tolerated
- Patients were given one vaccine injection only and monitored for 6 months thereafter to determine safety, tolerability, immune responsiveness such as IgG and IFN Gamma markers and disease markers such as CD4 and viral load count
- The results demonstrate that after a single immunization the HIV-v vaccine produces a very strong response from both the antibody and T cell immune systems to the conserved regions only. This is the first demonstration of an antibody response to a conserved internal protein that appears on the cell surface during the life-cycle of the HIV virus
- The six centres where the trial was conducted was North Manchester General Hospital; Grahame Hayton Unit of the Royal London Hospital; Elton John Centre at the Royal Sussex County Hospital; Royal Hallamshire Hospital, Sheffield; St. Stephen’s Centre at the Chelsea and Westminster Hospital, London; and St. Thomas’ Hospital, London.
HIV Facts
- Human Immunodeficiency virus (HIV) is the causative agent for Acquired Immune Deficiency Syndrome (AIDS). Infection with this retrovirus causes a progressive failure of the immune system making the host susceptible to opportunistic infections and cancers
- Currently, there are more than 33 million people living with HIV/AIDS worldwide, according to the World Health Organization, the majority of them in sub-Saharan Africa. Since 1980 over 25 million people have died as a result of HIV/AIDS. The infection has reached a pandemic status straining the economy of developing countries
- Treatment with a combination of several anti-retroviral (ARV) drugs has been successful in improving patients’ quality of life and lifespan. However this approach is costly and only widely-available in the developed world
- Only 6.5 million out of an estimated 17 million eligible for anti-retroviral (ARV) treatment are currently receiving treatment. UNAIDS estimates that $22 billion a year will be required by 2015 to ensure universal access to treatment care and support for people living with HIV/AIDS
- Long-term usage of ARVs also brings undesirable side-effects including cardiovascular complications, insulin-resistance, high levels of triglycerides, hypertension, and bone demineralization amongst others
- Long term treatment with ARVs induces the emergence of viral resistance to the ARVs, requiring higher doses and/or combinations of different ARVs
- HIV-v addresses all these issues and would provide a safe and low-cost alternative to ARVs
HIV Vaccine Facts
- The only hope to control the infection worldwide is a safe, effective and affordable vaccine. Vaccines can be protective (“prophylactic”), used to prevent infection, or curative (“therapeutic”), used to treat patients already infected with the virus
- To fight an intracellular pathogen such as the HIV virus, a cytotoxic Th1 response must be achieved. This response is characterised by activation of CD8+ lymphocyte T cells. These cells are capable of inducing killing of infected cells that in turn stops spreading of the infection
- A second strategy to combat HIV infection is the production of neutralising antibodies. Usually the immune system produces antibodies that are specific to proteins present in the external viral capsid of the HIV virus, i.e. not to internal proteins
- Most vaccines developed to date have been conventional vaccines that generate antibodies against the proteins that form the capsid (external coat) of the virus. Although these vaccines have been successful against a specific strain of HIV, the high rate of mutation of the virus (every 90 days) has meant that the protection was incomplete and not long lasting
- Other approaches to vaccine development targeted whole internal HIV proteins, which contain both conserved and highly-variable regions. Regions that are highly immunogenic will be under constant humoral immune pressure favouring the selection of new mutants to evade the immune response. That explains why highly variable regions are more immunogenic, i.e. a stronger immune response is mounted against them than against conserved regions. The cost of manufacturing whole proteins for a vaccine is very high, and an alternative approach is to deliver the DNA that codes for the protein instead. The DNA is inserted in a weakened virus used as a “vector” to allow entrance into the host’s cells. The whole protein is then produced within the cell using the host’s cell machinery. In some instances pre-existent immunity to the weakened viral vector has made vaccinated people more susceptible to HIV infection rather than protected against it
- The first sign of a promising vaccine was that used in a trial in Thailand, which combined two separate vaccines; one that targeted antibodies to the capsid proteins and one that targeted T cells to the internal proteins. While this showed a modest improvement it was not clinically significant
- HIV-v is a T and B cell vaccine that has produced clinically meaningful results due to its focus on conserved regions of the virus only
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