HIV Vaccines

Creative Biolabs is a well-known vaccine research and development company. The company has more than 10 years of experience in the field of vaccines. Comprehensive and in-depth R&D layout and perfect services make the company internationally trustworthy. We have continuous and embedded research and experimentation in the field of HIV vaccine, and have provided high-quality and reliable services to a large number of customers.

Human Immunodeficiency Virus (HIV)

HIV is an abbreviation for human immunodeficiency virus, a lentivirus that causes acquired immunodeficiency syndrome (AIDS), which is a disease that gradually damages the body's immune system, and patients eventually die from various pathogen infections and cancer. In the absence of treatment, HIV-infected patients typically have a survival time of 9-11 years. HIV is a sexually transmitted virus that can be transmitted through contact with or transfer of the blood or body fluids such as semen of infected people. In addition, the virus can also be transmitted from infected mothers to newborns during childbirth or lactation.

HIV belongs to the genus Lentivirus, which is a major cause of chronic diseases with long incubation periods. The lentiviral genome is positive, single-stranded enveloped RNA. When HIV enters a target cell, its genome is reverse transcribed into double-stranded DNA, which is then transported to the nucleus and integrated into the host DNA. The integration of the viral genome with the DNA of the host cell allows the virus to be latent, preventing virus and its host cells from being detected by body's immune system. HIV could be resting in the human body for ten years at most after the primary infection, during which the carriers do not show any symptoms. There is also the possibility that the integrated DNA is transcribed, so new viral genomes and proteins are produced, leading to the formation of new viral particles and their releases from the host cells, which ultimately initiate the viral replication cycle.

Fig.2 Replication cycle of HIV.

There are currently two confirmed HIV viruses, HIV-1 and HIV-2. HIV-1 is prevalent worldwide and is highly virulent and infectious, while HIV-2 is predominantly prevalent in West Africa, with relatively low virulence and infectivity. HIV has tropism for a variety of immune cells such as macrophages, CD4⁺ T cells, and microglia. HIV enters target cells through the interaction of its surface envelope protein gp120 with CD4 molecules on the surface of CD4⁺ T cells or macrophages with the assist of co-receptors such as other chemokines.

Immune Response That Correlates with HIV Protection

There are currently no approved vaccines in the world. The lack of innate immunity to HIV, the variability of viral epitopes in HIV, inadequate understanding of protective immunity correlations with HIV infection, and the difficulty in establishing reliable animal models that reflect the effectiveness of vaccines in humans make the development of HIV vaccines not so easy. 20-30% of patients are able to produce neutralizing antibodies that neutralize heterologous HIV Env epitopes about three years after HIV infection. Additional antibodies capable of binding to the CD4-binding regions of gp120, gp41 and gp140 have been identified (e.g., VCR01, 2G12, HGN194, and X5) and are believed to neutralize the virus by blocking the binding of the virus to cellular receptors. Passive vaccination of broadly neutralizing antibodies can provide protection to rhesus monkeys, so the induction of neutralizing antibodies is the focus of developing effective HIV vaccines. Non-neutralizing antibodies control viral infection by recruiting antigen-presenting cells, promoting ADCC (antibody-dependent cell-mediated cytotoxicity), and co-acting with antiviral cytokines, proteases to inhibit viral replication. The HIV vaccine clinical trial results show that non-neutralizing antibodies are more easily induced than neutralizing antibodies and do not require the maturation of B cells. In addition, such antibodies also provide protection through ADCC.

It is generally believed that cellular immune responses are more important than humoral immune responses in the control of HIV infection. The number of HIV-specific IL-2 secreting immature CD4⁺ T cells and HIV-specific mature CD8⁺ T cells are associated with control of HIV infection.

The Development of HIV Vaccine

• Live Attenuated and Inactivated Vaccines

  Vaccines of intact virions can induce an immune response similar to a real viral infection. Both live attenuated virus vaccines and inactivated virus vaccines have shown abilities to provide immunity in non-human primates. Formalin-inactivated simian immunodeficiency virus (SIV) is capable of inducing protection against the live virus in most immunized macaques. The nef-deleted SIV vaccine could induce complete protection in monkeys. The attenuated SIV strain, SIVmac293Δ3, which deleted the nef and vpr genes, also produced a protective effect, but the immune response provided is not long enough.

• Protein Subunit Vaccines

  Protein subunit vaccines gp140, gp160, gp120 are capable of producing neutralizing antibodies and activating CD4⁺ T cells, but their drawback is that they cannot produce CTL responses. The AIDSVAX B/B' vaccine prepared using the HIV-1 clade B gp120 protein and the clade B isolate showed good safety and immunogenicity in Phase I and Phase II clinical trials. However, the vaccine and another vaccine that passed Phase II clinical trials, AIDSVAX B/E, did not provide protection against HIV infection.

• Live Recombinant Vaccines

  HVTN 502 is a replication-defective recombinant adenovirus type 5 (rAd5) vaccine that expresses the nef, gag, pol protein of HIV-1 clade B. It has been found in clinical studies that the vaccination group still has a high infection rate. The researchers believe that the reason for this result may be that rAd5 may form a complex with its neutralizing antibodies and promote HIV infection of CD4⁺ T cells. ALVAC-HIV vCP1521 is a non-replicating recombinant canarypox virus (ALVAC) capable of expressing the gag/gol of HIV clade B and the env protein of CRF01_AE. The strategy of this vaccine is to use a live virus vector vaccine for primary immunization, and then use protein for booster immunization to obtain both cellular and humoral immune responses. Clinical trials showed that the vaccine was 61% protective after one year of inoculation, but the proportion dropped to half at the end of the trial.

• DNA Vaccines

  The vaccination strategy for HIV DNA vaccines is to immunize animals with DNA vaccine for a prime vaccination followed by a heterogonous boost or co-inoculation with the same antigen administrated by another vehicle.

• Electrophilic Vaccines (E-Vaccines)

  E-immunogens, which are vaccine candidates for microbial vaccines, use superepitope epitopes to bind to immunoglobulin framework regions (FRs) expressed as B cell receptors (BCR), thereby inhibiting the adaptive antibody response needed for protection against infection. Creative Biolabs is dedicated to the development of Electrophilic Vaccines against HIV which contains electrophilic polypeptides and binds covalently to B cells, resulting in widely neutralized antibodies.

Creative Biolabs is an excellent vaccine development and serving company. The company not only has a lot of achievements in the innovative research and development of vaccines but also continuously delivers its advanced technologies and experience to customers all over the world. We have an integrated research and development system and a complete service process. We can provide you with strategies for vaccine development and help you evaluate and optimize the immunogenicity of your vaccine, as well as any other products and services related to vaccine research.

All of our products can only be used for research purposes. These vaccine ingredients CANNOT be used directly on humans or animals.