Specificity of CD8 T-Cell Responses Following Vaccination with Conserved Regions of HIV-1 in Nairobi, Kenya.

Sub-Saharan Africa carries the biggest burden of the human immunodeficiency virus type 1 (HIV-1)/AIDS epidemic and is in an urgent need of an effective vaccine. CD8 T cells are an important component of the host immune response to HIV-1 and may need to be harnessed if a vaccine is to be effective. CD8 T cells recognize human leukocyte antigen (HLA)-associated viral epitopes and the HLA alleles vary significantly among different ethnic groups.

Randomized phase I trial HIV-CORE 003: Depletion of serum amyloid P component and immunogenicity of DNA vaccination against HIV-1.

Background: The failure of DNA vaccination in humans, in contrast to its efficacy in some species, is unexplained. Observational and interventional experimental evidence suggests that DNA immunogenicity may be prevented by binding of human serum amyloid P component (SAP). SAP is the single normal DNA binding protein in human plasma.

Long-term follow up of human T-cell responses to conserved HIV-1 regions elicited by DNA/simian adenovirus/MVA vaccine regimens.

Background: Durability of vaccine-elicited immune responses is one of the key determinants for vaccine success. Our aim is to develop a vaccination strategy against the human immunodeficiency virus type 1 (HIV-1), which induces protective and durable CD8+ T-cell responses. The central theorem of our approach is to focus T cells on highly conserved regions of the HIV-1 proteome and this is achieved through the use of the first-generation conserved vaccine immunogen HIVconsv.

Broad HIV-1 inhibition in vitro by vaccine-elicited CD8(+) T cells in African adults.

We are developing a pan-clade HIV-1 T-cell vaccine HIVconsv, which could complement Env vaccines for prophylaxis and be a key to HIV cure. Our strategy focuses vaccine-elicited effector T-cells on functionally and structurally conserved regions (not full-length proteins and not only epitopes) of the HIV-1 proteome, which are common to most global variants and which, if mutated, cause a replicative fitness loss. Our first clinical trial in low risk HIV-1-negative adults in Oxford demonstrated the principle that naturally mostly subdominant epitopes, when taken out of the context of full-length proteins/virus and delivered by potent regimens involving combinations of simian adenovirus and poxvirus modified vaccinia virus Ankara, can induce robust CD8(+) T cells of broad specificities and functions capable of inhibiting in vitro HIV-1 replication.

Control of HIV-1 replication in vitro by vaccine-induced human CD8(+) T cells through conserved subdominant Pol epitopes.

Objective: The specificity of CD8(+) T cells is critical for early control of founder/transmitted and reactivated HIV-1. To tackle HIV-1 variability and escape, we designed vaccine immunogen HIVconsv assembled from 14 highly conserved regions of mainly Gag and Pol proteins. When administered to HIV-1-negative human volunteers in trial HIV-CORE 002, HIVconsv vaccines elicited CD8(+) effector T cells which inhibited replication of up to 8 HIV-1 isolates in autologous CD4(+) cells.

Humoral responses to HIVconsv induced by heterologous vaccine modalities in rhesus macaques.

Vaccines delivering T cell immunogen HIVconsv vectored by plasmid DNA, non-replicating simian adenovirus and non-replicating modified vaccinia virus Ankara (MVA) are under clinical evaluation in phase I/IIa trials in UK, Europe, and Africa. While these vaccines aim to induce effector T cell responses specific for HIV-1, we here characterized the humoral responses induced by HIVconsv administration to macaques using six different vaccine modalities: plasmid DNA, human adenovirus serotype 5, simian adenovirus serotype 63, MVA, Semliki Forest virus replicons, and adjuvanted overlapping synthetic long peptides (SLP). We found that only the SLP formulation, but none of the genetic vaccine platforms induced antibodies recognizing linear HIVconsv epitopes, median 32/46 SLP.

The biology of micrometastases from uveal melanoma.

Background: The aim of this study was to investigate the possible causes of tumour latency in uveal melanoma primarily through the analysis of micrometastases in tissue obtained from donors postmortem. Various explanations have been proposed but there is no clear answer from animal studies and few human data. The main hypotheses may be divided into several areas--immunological control of metastatic cells, lack of angiogenesis within micrometastases and reduced cell turnover.

Melanoma vaccines: The problems of local immunosuppression.

The incidence of cutaneous melanoma in Europe is rising, and the disease is incurable once metastases occur. Because melanoma expresses antigens that can be specifically recognized by the immune system, and because this disease occasionally undergoes spontaneous regression mediated by anti-tumor immunity, a number of different melanoma vaccines have been developed and tested clinically. Although most such vaccines show efficacy in vitro and an ability to stimulate anti-melanoma immune responses in blood, they have proved disappointing in clinical practice.

Activation of tonsil dendritic cells with immuno-adjuvants.

Background: Dendritic cells (DC) play the key role in directing antigen-specific immune responses and manipulating their function may be a useful tool for immunotherapy. The balance between immune stimulation and tolerance is particularly important at mucosal interfaces, where discrimination between dangerous pathogens and innocuous antigens takes place. In humans, although much is known about the responses of monocyte derived DC, relatively little is known about effect of immuno-stimulatory adjuvants on DC found in tonsil.

Presence and phenotype of dendritic cells in uveal melanoma.

Background: Uveal melanoma arises in an immune-privileged site and can itself add to the immunosuppressive environment. Previous studies on cutaneous melanoma have shown the presence of tolerogenic dendritic cells (DCs), which could play an important role in the progression of the tumour.

Aim: To examine the presence and functional status of DCs in a small series of uveal melanomas.

Post-menopausal bleeding: a rare presentation of metastatic uveal melanoma.

Uveal melanoma differs from cutaneous melanoma in many ways, including its pattern of metastasis, and exhibits latency with clinical evidence of metastasis sometimes appearing many years after primary diagnosis. Most patients develop metastasis within the liver, but some may present with metastasis to other sites. We report a case of uveal melanoma that presented with post-menopausal bleeding due to metastasis.

Presence and maturity of dendritic cells in melanoma lymph node metastases.

Immune avoidance mechanisms play a key role in the successful dissemination of melanoma. One mechanism whereby this could be achieved is by interfering with dendritic cell (DC) presentation of tumour-associated antigens to naïve T cells. In particular, immature DCs characterized by the absence of accessory molecules are known to be immunosuppressive and to be involved in the induction of tolerance.

Virus-specific CTL responses induced by an H-2K(d)-restricted, motif-negative 15-mer peptide from the fusion protein of respiratory syncytial virus.

We describe 15-mer peptide P8:F92-106 from the F protein of respiratory syncytial virus (RSV) that can act as an MHC class I-restricted (H-2K(d)) epitope for RSV-specific CD8(+) CTL. This peptide is interesting because not only is it the first murine CTL epitope to be identified in the F protein but also because it does not contain a known allele-specific motif, as all 15 amino acids appear to be required for effective presentation to CTL. In in vitro MHC class I refolding experiments, peptide P8:F92-106 induced complex formation with H-2K(d) heavy chains and beta2-microglobulin.