HIV-1 vaccine clinical trials: the Brazilian experience

Human Immunodeficiency Virus Proteins Mimic Human T Cell Receptors Inducing Cross-Reactive Antibodies

Human immunodeficiency virus (HIV) hides from the immune system in part by mimicking host antigens, including human leukocyte antigens. It is demonstrated here that HIV also mimics the V-β-D-J-β of approximately seventy percent of about 600 randomly selected human T cell receptors (TCR). This degree of mimicry is greater than any other human pathogen, commensal or symbiotic organism studied. These data suggest that HIV may be evolving into a commensal organism just as simian immunodeficiency virus has done in some types of monkeys. The gp120 envelope protein, Nef protein and Pol protein are particularly similar to host TCR, camouflaging HIV from the immune system and creating serious barriers to the development of safe HIV vaccines. One consequence of HIV mimicry of host TCR is that antibodies against HIV proteins have a significant probability of recognizing the corresponding TCR as antigenic targets, explaining the widespread observation of lymphocytotoxic autoantibodies in acquired immunodeficiency syndrome (AIDS). Quantitative enzyme-linked immunoadsorption assays (ELISA) demonstrated that every HIV antibody tested recognized at least one of twelve TCR, and as many as seven, with a binding constant in the 10-8 to 10-9 m range. HIV immunity also affects microbiome tolerance in ways that correlate with susceptibility to specific opportunistic infections.

Vaccine research, development, and innovation in Brazil: a translational science perspective

This article examines the Brazilian innovation policy for vaccines and its impact on infectious diseases, with emphasis on advances in translational science. The results indicate significant progress, with a rapid increase over the past two decades in the number of vaccine research groups, indicating scientific excellence. Advances and gaps in technological development and in public-private partnership initiatives were also identified. We stress the crucial role of partnerships, technology transfer, and targeted policies that could accelerate Brazil's participation in global vaccine research and development. We propose that new strategies should be urgently conceived to strengthen the links between the scientific and technological policies, the National Health System, and the National Immunizations Program in Brazil to provide access to low-cost vaccines to address major public health challenges. We also discuss the lessons learned from the Brazilian experience in the implementation of governmental policies on vaccine innovation that could be applicable to other developing countries.

A brief history of the global effort to develop a preventive HIV vaccine

Soon after HIV was discovered as the cause of AIDS in 1983-1984, there was an expectation that a preventive vaccine would be rapidly developed. In trying to achieve that goal, three successive scientific paradigms have been explored: induction of neutralizing antibodies, induction of cell mediated immunity, and exploration of combination approaches and novel concepts. Although major progress has been made in understanding the scientific basis for HIV vaccine development, efficacy trials have been critical in moving the field forward. In 2009, the field was reinvigorated with the modest results obtained from the RV144 trial conducted in Thailand. Here, we review those vaccine development efforts, with an emphasis on events that occurred during the earlier years. The goal is to provide younger generations of scientists with information and inspiration to continue the search for an HIV vaccine.

HIV-1 genetic diversity and drug resistance among treatment naïve patients from Southern Brazil: an association of HIV-1 subtypes with exposure categories

BACKGROUND

The AIDS epidemic in Southern Brazil has unique features, showing co-circulation of HIV-1 subtypes C, B and recombinant forms. Florianópolis has the second highest AIDS incidence among Brazilian capitals, but limited information is available about HIV molecular epidemiology and prevalence of primary drug resistance.

OBJECTIVES

To investigate the molecular epidemiology of HIV-1 in Florianópolis and to describe the prevalence of primary HIV-1 drug resistance mutations (DMRs).

STUDY DESIGN

Epidemiological and clinical data from 82 untreated patients from Florianópolis (2008-2009) were analyzed. The HIV-1 subtype at envelope, protease, reverse transcriptase and integrase regions were determined by phylogenetic and bootscaning analyses and the drug resistance profile were analyzed at the Stanford HIV Drug Resistance Database.

RESULTS

The most frequent HIV-1 genetic form was subtype C (65.8%) followed by mosaics BC (18.3%), subtype B (13.4%), subtype F1 (1.2%) and BCF1 recombinant (1.2%). HIV-1 subtype C and BC recombinants were much more frequent in the heterosexual exposure category, whereas subtype B was more common in the MSM exposure category. DRMs were seen in 11% of the sequences, 2.4% of them were related to PI, 5% to NRTI, 3.6% to NNRTI and 1.2% was related to INTI.

CONCLUSIONS

The present study confirms the high prevalence of subtype C and BC recombinants in Santa Catarina State and revealed a significant difference in the subtype distribution among distinct virus exposure categories. This study also shows a relative high prevalence of protease/reverse transcriptase primary drug resistance mutations and corroborates the usefulness of the integrase inhibitors in southern Brazil.