Progress in vaccine development against SIV and HIV
Article Abstract:
Recent advancements in the development of a vaccine against the human immunodeficiency virus type-1 (HIV-1) have caused some optimism, when it was felt that the problems were insurmountable. One of the most important of these advances is the development of effective vaccines against the simian immunodeficiency virus (SIV) and equine infectious anemia virus (EIAV), which serve as animal models for HIV. Whole virus, which has been killed, has been used as a vaccine and causes a delayed onset of disease. In some cases, the disease does not develop at all. The delay of the onset of disease occurs even though the virus is still able to cause an infection. This implies that the virus does not have to be completely eliminated and that infection may not have to be stopped for a vaccine to be successful. Using these animal models, the molecules that are responsible for instilling protection and the mechanisms of protection can be studied. Another important advancement toward the development of a vaccine is the understanding of the epitopes, or the particular regions on molecules that provoke an immune response. The main epitope to which an antibody response is made, which neutralizes or inhibits the virus from attaching to cells, has been identified. This epitope is located on the envelope protein of the virus, which forms the outer coat of the virus particle. Studies have shown that when animals are given antibodies to this region along with the virus, the antibodies can protect the animals from developing an infection with HIV. If a peptide containing the epitope is administered to animals, the animals produce large amounts of antibodies which stop the virus from causing an infection. The antibodies also protect against future infections with the virus for a certain period of time. Therefore, recent advancements have been made, which bring scientists closer to the development of a vaccine against AIDS. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Journal of Acquired Immune Deficiency Syndromes
Subject: Health
ISSN: 0894-9255
Year: 1990
User Contributions:
Comment about this article or add new information about this topic:
Export and one-step purification from Escherichia coli of a MalE-CD4 hybrid protein that neutralizes HIV in vitro
Article Abstract:
The human immunodeficiency virus (HIV) binds to the CD4 molecule on T lymphocytes via the gp160 molecule, the protein of the envelope, or coat, that surrounds the virus. The virus can then enter into these immune cells and eventually destroy them, effectively blocking an immune response. CD4 molecules that are soluble, that is, free from the cell surface, bind to HIV and inhibit the virus from binding to CD4 on the cell surface. The DNA sequence which encodes a portion of the CD4 molecule has been attached to a portion of the gene coding for a bacterial protein, MalE, the periplasmic maltose-binding protein, and cloned in the bacteria Escherichia coli. Because the hybrid molecule contains the MalE sequences, the molecule is transported into the periplasm of E. coli and binds to maltodextrins. Molecules in the periplasm can be easily released by lysing the cells. Other molecules which have been expressed in bacteria are often insoluble and cannot readily be released. The hybrid molecule can be purified, or separated, from the other molecules, by its ability to bind to the molecule amylose. In laboratory tests, the hybrid molecule is found to bind to the HIV envelope protein and render the virus inactive. This hybrid molecule can potentially be used to inhibit the virus from binding to CD4 molecules in the body. Since it is produced in bacteria and is easily purified, large amounts of the protein could be produced. Soluble CD4 molecules are usually removed quickly by the body, but since this molecule is larger, it may be stable longer and take longer to be eliminated from the body. The MalE portion of the molecule may also stimulate an immune reaction, which could help eliminate the virus from the body when the molecule is bound to it. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Journal of Acquired Immune Deficiency Syndromes
Subject: Health
ISSN: 0894-9255
Year: 1990
User Contributions:
Comment about this article or add new information about this topic:
Alcohol consumption and unsafe sex: a comparison of heterosexual and homosexual men
Article Abstract:
Consumption of alcohol is associated with sexual behavior that may lead to an increased risk of infection with the human immunodeficiency virus (HIV). A survey was conducted of 844 adults, whose average age was 35 years and who lived in the San Francisco area, concerning the circumstances of specific sexual encounters that occurred when they consumed alcohol. Forty-eight percent of the participants were female and 52 percent were male. Seventy-six percent were heterosexual and 24 percent were bisexual or homosexual. When alcohol was not being consumed, heterosexuals were more likely to use unsafe sexual practices (sex without the use of condoms). Homosexual men, who are at greater risk of contracting HIV, generally used safe sexual behavior. However, if under the influence of alcohol, homosexual men and heterosexual women, but not heterosexual men, were more likely to practice unsafe sex. Safe sexual behavior was more often practiced when the sexual partners met each other in ''pick-up'' environments. It is concluded that the results of this study, which focuses on specific sexual events, can be used to better appreciate the dynamics of sexual encounters and aid in the control of behavior that has a high risk. The small sample size is noted by the authors as a limitation of the study. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Journal of Acquired Immune Deficiency Syndromes
Subject: Health
ISSN: 0894-9255
Year: 1991
User Contributions:
Comment about this article or add new information about this topic:
- Abstracts: Protein-metabolism kinetics and energy-substrate utilization in infants fed parenteral solutions with different glucose-fat ratios
- Abstracts: The effects of weight loss on activity and expression of adipose-tissue lipoprotein lipase in very obese humans
- Abstracts: A 65-year-old man with a vertebral and disk lesion after a pulmonary operation for aspergillus infection (Case 11-1991) (Case Records of the Massachusetts General Hospital)
- Abstracts: Microscopic colitis. Evaluation of the efficacy of oral rehydration solutions using human whole gut perfusion
- Abstracts: Necrotizing myopathy in critically-ill patients. Catabolic effects of high-dose corticosteroids persist despite therapeutic benefit in rheumatoid arthritis