CD8+ T cell recognition of epitopes within the capsid of adeno-associated virus 8-based gene transfer vectors depends on vectors' genome.

Self-complementary adeno-associated viral (AAV) vectors expressing human factor IX (hF.IX) have achieved transient or sustained correction of hemophilia B in human volunteers. High doses of AAV2 or AAV8 vectors delivered to the liver caused in several patients an increase in transaminases accompanied by a rise in AAV capsid-specific T cells and a decrease in circulating hF.

Effects of immunosuppression on circulating adeno-associated virus capsid-specific T cells in humans.

In humans adeno-associated virus (AAV)-mediated gene transfer is followed by expansion of AAV capsid-specific T cells, evidence of cell damage, and loss of transgene product expression, implicating immunological rejection of vector-transduced cells, which may be prevented by immunosuppressive drugs. We undertook this study to assess the effect of immunosuppression (IS) used for organ transplantation on immune responses to AAV capsid antigens. Recipients of liver or kidney transplants were tested before and 4 weeks after induction of IS in comparison with matched samples from healthy human adults and an additional cohort with comorbid conditions similar to those of the transplant patients.

Hexon-modified recombinant E1-deleted adenovirus vectors as dual specificity vaccine carriers for influenza virus.

To determine if an ordered and repetitive display of an epitope promoted induction of superior antibody responses, we compared B-cell responses to an influenza A virus epitope that was either encoded as a transgene by an adenovirus (Ad) vector or expressed on the vector's surface. To this end, we constructed a panel of influenza A virus vaccines based on chimpanzee-derived replication-defective adenovirus (AdC) vectors of serotype SAd-V25 also called AdC68. AdC68 vectors were modified to express a linear B-cell epitope of the ectodomain of matrix 2 (M2e) within variable regions 1 (VR1) or 4 (VR4) of the adenovirus hexon.

Self-complementary AAVs induce more potent transgene product-specific immune responses compared to a single-stranded genome.

Using a mouse model we show that self-complementary (sc) adeno-associated virus (AAV) vectors pseudotyped with capsids of serotypes 2, 7 or 8 induce more potent transgene product-specific CD8(+) T cell and antibody responses compared to corresponding single-stranded (ss)AAV vectors. These data suggest that the higher and more rapidly appearing amounts of transgene product achieved with scAAV vectors may increase detrimental immune responses in gene transfer recipients.

Viral delivery for gene therapy against cell movement in cancer.

Viral delivery for cancer gene therapy is a promising approach, where traditional radiotherapy or chemotherapy to limit proliferation and movement of cancer cells has met resistance. Based on the new understanding of the biology of the viral vectors, therapeutic viral vectors for cancer gene therapy have been improved for greater safety and efficacy as well as transitioned from being non-replicating to replication-competent. Traditional oncolytic vectors have focused on eliminating tumor growth, while novel vectors simultaneously target epithelial-to-mesenchymal transition (EMT) in cancer cells, which could further prevent and reverse the aggressive tumor progression.

Adeno-associated virus vectors serotype 2 induce prolonged proliferation of capsid-specific CD8+ T cells in mice.

Using adoptive transfer models we determined that an adeno-associated viral vector of serotype 2 (AAV2) induces in mice proliferation of CD8(+) T cells that recognize an epitope within the viral capsid. Proliferation to an endogenous epitope within viral protein (VP)3 could be observed for at least 3 weeks while a foreign epitope placed at multiple copies within VP2 elicited CD8(+) T cell expansion for at least 10 weeks. These data show that capsid antigens of AAV2 degrade slowly over a period of weeks and during this period provide targets to CD8(+) T cells.

Vaccine-induced T cells provide partial protection against high-dose rectal SIVmac239 challenge of rhesus macaques.

Despite enormous efforts by the scientific community, an effective HIV vaccine remains elusive. To further address to what degree T cells in absence of antibodies may protect against simian immunodeficiency virus (SIV) disease progression, rhesus macaques were vaccinated intramuscularly with a chimpanzee-derived Ad vector (AdC) serotype 6 and then boosted intramuscularly with a serologically distinct AdC vector of serotype 7 both expressing Gag of SIVmac239. Animals were subsequently boosted intramuscularly with a modified vaccinia Ankara (MVA) virus expressing Gag and Tat of the homologous SIV before mucosal challenge with a high dose of SIVmac239 given rectally.

Immune barriers to successful gene therapy.

Immune responses to viral vectors pose one of the main obstacles to successful human gene replacement therapy, unless gene transfer vectors are applied to immune-privileged sites. Both innate and adaptive immunity work in concert against sustained gene transfer, but the functions of patients' regulatory T cells (Tregs) and tolerogenic dendritic cells (DCs) could potentially be harnessed to reduce these immune responses. Over the last few years, immunologists have gained an ever-increasing knowledge of immunoregulatory pathways, especially those that prevent or dampen adaptive immune responses.

A more precise HIV integration assay designed to detect small differences finds lower levels of integrated DNA in HAART treated patients.

Many studies report the level of total viral DNA in HIV-infected patients, but few studies report the level of integrated DNA. It is important to measure integrated DNA in HIV-infected patients because the information could shed light on the effectiveness of antiretroviral therapy, especially intensified therapy, when viral loads may remain undetectable. In order to develop an integration assay for patient samples, we enhanced the sensitivity of our prior integration assay.

Efficacy and safety of statins in hypercholesterolemia with emphasis on lipoproteins.

Information of the effect of statin on lipoproteins such as apolipoprotein (apo) A-I, lipoprotein (a) [Lp (a)], or apolipoprotein B levels is limited. This investigation was a crossover study designed to evaluate the efficacy and safety of atorvastatin and simvastatin in patients with hyperlipidemia. Sixty-six patients were involved in the study.