Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Centers for Disease Control and Prevention (CDC) states that there is no evidence that dogs, cats or non-primate animals can contract the human immunodeficiency virus (HIV) or transmit it to human beings. When the immune system is suppressed through disease, age, or medical treatments, a person becomes more vulnerable to infections. Pets Are Wonderful Support (PAWS) has developed guidelines for having pets. Proper pet selection, proper pet care and good personal hygiene of the owner can eliminate almost any possible risk a pet poses. New pets pose more of a health risk because health history and vaccination records are usually not known. Adult pets are often safer, and are less likely to be involved in playful activities that include biting and scratching. There is a slim chance of contracting toxoplasmosis from cats, but certain precautions can minimize risk. Annual veterinarian examinations are recommended to keep vaccinations current. The CDC does not recommend keeping a cat with feline leukemia virus or feline immunodeficiency virus since these diseases can make the cat more susceptible to other illnesses which can be passed on to a person with a compromised immune system. Turtles and birds are not recommended since they may harbor diseases. Several services are available to pet owners and are listed in the article.
STEP Perspect 1995
PMID:HIV and pet ownership. 1136 98

During the 6th Conference on Retroviruses and Opportunistic Infections (CROI), researchers at the University of Alabama reported that they have traced the origin of AIDS to a subspecies of chimpanzees (Pan troglodytes) found in Africa. Studies of simian immunodeficiency virus (SIV), which is harmless in chimpanzees, may facilitate understanding about HIV transmission and the immune system response. Unfortunately the chimpanzees are being eradicated by hunters and the logging trade. Scientists speculate that these practices may spread SIV and other viruses further to the human population. More research is needed before information useful to the epidemic in humans is found.
STEP Perspect 1999
PMID:Origin of AIDS discovered. 1136 66

The adenovirus type 5 (Ad5)-based vaccine developed by Merck failed to either prevent HIV-1 infection or suppress viral load in subsequently infected subjects in the STEP human Phase 2b efficacy trial. Analogous vaccines had previously also failed in the simian immunodeficiency virus (SIV) challenge-rhesus macaque model. In contrast, vaccine protection studies that used challenge with a chimeric simian-human immunodeficiency virus (SHIV89.6P) in macaques did not predict the human trial results. Ad5 vector-based vaccines did not protect macaques from infection after SHIV89.6P challenge but did cause a substantial reduction in viral load and a preservation of CD4+ T cell counts after infection, findings that were not reproduced in the human trials. Although the SIV challenge model is incompletely validated, we propose that its expanded use can help facilitate the prioritization of candidate HIV-1 vaccines, ensuring that resources are focused on the most promising candidates. Vaccine designers must now develop T cell vaccine strategies that reduce viral load after heterologous challenge.
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PMID:Nonhuman primate models and the failure of the Merck HIV-1 vaccine in humans. 1853 79

HIV infection, once established, is never cleared. Rare individuals do, however, control viral replication to low levels. These successful immune responses are primarily linked to certain class I MHC alleles (MHC-I). Because of this association, many AIDS vaccines in development are designed to generate virus-specific CD8+ T cells. The Merck STEP phase 2b efficacy trial of one such vaccine was recently halted, and declared a failure. Thus, basic questions regarding what constitutes an effective T cell response and how such responses could be elicited by vaccination remain open. The best animal model available to explore such issues is simian immunodeficiency virus infection of rhesus macaques, which serves as the primary proving ground for AIDS vaccines.
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PMID:Relevance of studying T cell responses in SIV-infected rhesus macaques. 1896 16

Adenovirus (Ad) vectors were initially developed for treatment of genetic diseases. Their usefulness for permanent gene replacement was limited by their high immunogenicity, which resulted in rapid elimination of transduced cells through induction of T and B cells to antigens of Ad and the transgene product. The very trait that excluded their use for sustained treatment of genetic diseases made them highly attractive as vaccine carriers. Recently though results showed that Ad vectors based on common human serotypes, such as serotype 5, may not be ideal as vaccine carriers. A recently conducted phase 2b trial, termed STEP trial, with an AdHu5-based vaccine expressing antigens of human immunodeficiency virus 1 (HIV-1) not only showed lack of efficacy in spite of the vaccine's immunogenicity, but also suggested an increased trend for HIV acquisition in individuals that had circulating AdHu5 neutralizing antibodies prior to vaccination. Alternative serotypes from humans or nonhuman primates (NHPs), to which most humans lack pre-existing immunity, have been vectored and may circumvent the problems encountered with the use of AdHu5 vectors in humans. In summary, although Ad vectors have seen their share of setbacks in recent years, they remain viable tools for prevention or treatment of a multitude of diseases.
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PMID:New insights on adenovirus as vaccine vectors. 1951 19

The Merck STEP and the Thai RV144 human immunodeficiency virus (HIV) vaccine trials confirmed that we still have a long way to go before developing a prophylactic HIV vaccine. The main issue at hand is that we have yet to identify an immunological correlate of protection against HIV. While many question the T-cell-based approach towards vaccine development, it is likely that T cells will be a necessary part of any vaccine strategy. CD8(+) T cells remain an attractive option because of their ability to specifically recognize and eliminate virally infected host cells. In this review, we recapitulate the evidence for CD8(+) T cells as an immunological correlate against HIV, but more importantly, we assess the means by which we evaluate their antiviral capacity. To achieve a breakthrough in the domain of T-cell-based HIV vaccine development, it has become abundantly clear that we must overhaul our system of immune monitoring and come up with a 'rational' tactic to evaluate the efficacy of HIV-specific CD8(+) T cells.
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PMID:Living in a house of cards: re-evaluating CD8+ T-cell immune correlates against HIV. 2119 68

A safe, efficacious vaccine is required to stop the AIDS pandemic. Disappointing results from the STEP trial implied a need to include humoral anti-HIV-1 responses, a notion supported by RV144 trial data even though correlates of protection are unknown. We vaccinated rhesus macaques with recombinant simian immunodeficiency virus (SIV) Gag-Pol particles, HIV-1 Tat and trimeric clade C (HIV-C) gp160, which induced cross-neutralizing antibodies (nAbs) and robust cellular immune responses. After five low-dose mucosal challenges with a simian-human immunodeficiency virus (SHIV) that encoded a heterologous R5 HIV-C envelope (22.1% divergence from the gp160 immunogen), 94% of controls became viremic, whereas one third of vaccinees remained virus-free. Upon high-dose SHIV rechallenge, all controls became infected, whereas some vaccinees remained aviremic. Peak viremia was inversely correlated with both cellular immunity (p<0.001) and cross-nAb titers (p<0.001). These data simultaneously linked cellular as well as humoral immune responses with the degree of protection for the first time.
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PMID:Vaccination against heterologous R5 clade C SHIV: prevention of infection and correlates of protection. 2179 65

To explore the efficacy of novel complementary prime-boost immunization regimens in a nonhuman primate model for HIV infection, rhesus monkeys primed by different DNA vaccines were boosted with virus-like particles (VLP) and then challenged by repeated low-dose rectal exposure to simian immunodeficiency virus (SIV). Characteristic of the cellular immune response after the VLP booster immunization were high numbers of SIV-specific, gamma interferon-secreting cells after stimulation with inactivated SIV particles, but not SIV peptides, and the absence of detectable levels of CD8(+) T cell responses. Antibodies specific to SIV Gag and SIV Env could be induced in all animals, but, consistent with a poor neutralizing activity at the time of challenge, vaccinated monkeys were not protected from acquisition of infection and did not control viremia. Surprisingly, vaccinees with high numbers of SIV-specific, gamma interferon-secreting cells were infected fastest during the repeated low-dose exposures and the numbers of these immune cells in vaccinated macaques correlated with susceptibility to infection. Thus, in the absence of protective antibodies or cytotoxic T cell responses, vaccine-induced immune responses may increase the susceptibility to acquisition of immunodeficiency virus infection. The results are consistent with the hypothesis that virus-specific T helper cells mediate this detrimental effect and contribute to the inefficacy of past HIV vaccination attempts (e.g., STEP study).
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PMID:Risk of immunodeficiency virus infection may increase with vaccine-induced immune response. 2281 18

The failure of the adenovirus serotype 5 (Ad5) vector-based human immunodeficiency virus type 1 (HIV-1) vaccine in the STEP study has led to the development of adenovirus vectors derived from alternative serotypes, such as Ad26, Ad35, and Ad48. We have recently demonstrated that vaccines using alternative-serotype Ad vectors confer partial protection against stringent simian immunodeficiency virus (SIV) challenges in rhesus monkeys. However, phenotypic differences between the T cell responses elicited by Ad5 and those of alternative-serotype Ad vectors remain unexplored. Here, we report the magnitude, phenotype, functionality, and recall capacity of memory T cell responses elicited in mice by Ad5, Ad26, Ad35, and Ad48 vectors expressing lymphocytic choriomeningitis virus (LCMV) glycoprotein (GP). Our data demonstrate that memory T cells elicited by Ad5 vectors were high in magnitude but exhibited functional exhaustion and decreased anamnestic potential following secondary antigen challenge compared to Ad26, Ad35, and Ad48 vectors. These data suggest that vaccination with alternative-serotype Ad vectors offers substantial immunological advantages over Ad5 vectors, in addition to circumventing high baseline Ad5-specific neutralizing antibody titers.
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PMID:Alternative serotype adenovirus vaccine vectors elicit memory T cells with enhanced anamnestic capacity compared to Ad5 vectors. 2315 35

Human immunodeficiency virus (HIV) vaccine preparedness studies (VPSs) have taken place in both the Organisation for Economic Co-operation and Development (OECD) countries and the non-OECD countries. HIV VPSs are conducted to assess the feasibility of phase 3 HIV vaccine trials. This descriptive review is an update of HIV VPSs in the non-OECD countries, and examines the willingness to participate (WTP) in hypothetical HIV vaccine trials, as well as retention. Few VPSs have been published in the OECD countries since the discontinuation of the STEP/Phambili HIV vaccine trials. Barriers to participation in the non-OECD countries after the STEP/Phambili studies include safety issues and side effects, vaccine-induced seropositivity (VISP) and mistrust among key informants (KIs). HIV VPSs indicate that HIV vaccine trials are still feasible in the non-OECD countries, but barriers must be overcome to improve feasibility. Hypothetical WTP in a VPS may not translate into actual WTP in an HIV vaccine trial.
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PMID:An update on human immunodeficiency virus vaccine preparedness studies. 2590 8


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