Track topics on Twitter Track topics that are important to you
Hypothesis: Treatment with raltegravir does not alter V(D)J recombination or immune responses to neoantigens.
A process known as V(D)J recombination is essential for developing lymphocytes and the specific functioning of the immune system. Raltegravir is the first approved drug of the new integrase inhibitor class of anti-HIV drugs. Integrase inhibitors have been shown in some studies to interfere with DNA cleavage and the activities of RAG-1/2. These studies suggest a potential to affect aspects of both B-cell and T-cell development, therefore, it is important to evaluate the potential effects that integrase inhibitors may have in clinical use. If immunoglobulin and T-cell receptor genes are altered by HIV integrase, then patient lymphocytes will fail to display normal responses to vaccinations.
V(D)J recombination is essential for developing lymphocytes and the specific functioning of the immune system. Germline gene coding segments become rearranged to create functional immunoglobulin and T-cell receptor genes by this recombination. The process depends on site-specific cleavage of chromosomal DNA by RAG-1 and RAG-2 recombinase. Two recombination-activating gene proteins (RAG-1/2) in conjunction make up a complex of enzymes that join gene segments of B-cell and T-cell receptor genes. RAG-1 contains most of the V(D)J recombinase active site and RAG-2 is essential in joining DNA segments during V(D)J recombination. RAG-1/2 have similarity in action to other DNA transposases and HIV-1 integrase. These similarities suggest that HIV-1 integrase inhibitors may have the potential to affect aspects of both B-cell and T-cell development.
Induction of primary immune responses to neoantigens involves the generation of specific T-cells and immunoglobulin M (IgM) antibody secreting B-cells. As part of this process, T and B memory cells are also generated, which have specific cell surface receptors to the antigen. On repeat exposure to the antigen, these memory T- and B-cells are triggered to generate rapid and intense secondary responses. During this secondary response, B-cells secrete abundant specific IgG antibodies with greater affinity to the antigen than for the IgM isotope. This memory response is mediated by T-cells with CD45+ RO+ phenotype. These T-cells provide B-cells the help required to generate the specific IgG. Sub-optimal antibody responses are seen in both acquired and hereditary immunodeficiency, which are due to impaired T-cell function including poor T-helper responses to B-cells and defective neo-antigen responses.
An established method to evaluate T-cell function involves testing antibody production to vaccination with phiX174, a stable bacteriophage of E. Coli that is critical in demonstrating T-cell competence. Antibody titers after primary and secondary immunization correlate with abnormal CD4 cell help. Patients with functional B-cells that lack T-cell help show a characteristic failure to switch from IgM to IgG, making this assay essential in the evaluation of V(D)J recombination.
Currently, raltegravir is the only approved integrase inhibitor that targets the integration stage of the HIV-1 lifecycle. The clinical manifestations of raltegravir-related potential adverse effects on V(D)J recombination may be so rare that they may only be observed after large numbers of patients are exposed to this drug. Evaluating the direct in vivo interaction of HIV integrase inhibitors on RAG-1/2 is difficult, therefore the best approach may be to evaluate the potential negative effects on recombinase activity downstream by studying immune function. If gene rearrangements of immunoglobulin and T-cell receptor genes are altered by HIV integrase, then patient lymphocytes will fail to display normal responses to neo-antigen exposure. Since untreated HIV-infected individuals have an impaired ability to respond to new antigens, it is difficult to evaluate the responses to neo-antigens in these individuals. Therefore, to test this hypothesis, it would be best to choose patients with long-term control of HIV that have recovered immune function.
Allocation: Randomized, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Basic Science
Immune Deficiency Treatment Centre, Montreal General Hospital, McGill University Health Centre
McGill University Health Center
Published on BioPortfolio: 2015-05-03T15:25:42-0400
The purpose of this study is to test three experimental HIV vaccines. This study will look at whether it is safe to give these vaccines together and how the immune system responds to the ...
The purpose of this study is to evaluate the long-term consequences of HIV-1 infections that occurred in association with known, but discouraged, high-risk behaviors in persons who have re...
This screening study will evaluate potential study volunteers with HIV infection to see if they are suitable candidates for trials of experimental vaccines against HIV (therapeutic), and a...
The purpose of this study is to see if the vaccines tested are safe when given alone and when given together, and how the immune system responds to the vaccines. Vaccines are given to peo...
The purpose of this study is to see if it is safe to give an HIV vaccine (vCP205) to volunteers who received an HIV vaccine at least 2 years ago, and to study how the immune system respond...
Salmonella infections are a common bacterial cause of invasive disease in people with sickle cell disease especially children, and are associated with high morbidity and mortality rates. Although avai...
In addition to vaccines' specific effects, vaccines may have non-specific effects (NSEs) altering the susceptibility to unrelated infections. Non-live vaccines have been associated with negative NSEs....
Infectious complications are one of the leading causes of hospitalization and mortality in kidney transplant recipients. They are more frequent during the year following transplantation, and in the el...
The co-evolution of the microbiota and immune system has forged a mutually beneficial relationship. This relationship allows the host to maintain the balance between active immunity to pathogens and v...
Prophylactic vaccines are efficacious in preventing Human Papillomavirus (HPV) infection and subsequent cervical intraepithelial neoplasia (CIN), cervical cancer, other anogenital cancers, and anogeni...
Vaccines or candidate vaccines used to prevent PAPILLOMAVIRUS INFECTIONS. Human vaccines are intended to reduce the incidence of UTERINE CERVICAL NEOPLASMS, so they are sometimes considered a type of CANCER VACCINES. They are often composed of CAPSID PROTEINS, especially L1 protein, from various types of ALPHAPAPILLOMAVIRUS.
Vaccines or candidate vaccines used to prevent infections with STREPTOCOCCUS PNEUMONIAE.
Vaccines or candidate vaccines used to prevent or treat PSEUDOMONAS INFECTIONS.
Vaccines or candidate vaccines used to prevent STREPTOCOCCAL INFECTIONS.
Vaccines or candidate vaccines used to prevent or treat both enterotoxigenic and enteropathogenic Escherichia coli infections.
Blood is a specialized bodily fluid that delivers necessary substances to the body's cells (in animals) – such as nutrients and oxygen – and transports waste products away from those same cells. In vertebrates, it is composed of blo...
Pharmacy is the science and technique of preparing as well as dispensing drugs and medicines. It is a health profession that links health sciences with chemical sciences and aims to ensure the safe and effective use of pharmaceutical drugs. The scope of...
Human Immuno Deficiency Virus (HIV)
Human Immunodeficiency Virus (HIV), the causative agent of AIDS. The Human Immunodeficiency Virus, more commonly known as HIV, is a member of the lentivirus sub-set of the retrovirus family of pathogens. It causes AIDS, or Acquired Immuno Deficiency Sy...