Immunology research update from Immunopaedia.org.za.
There have been many advances in HIV care and treatment over the past 40 years. Despite these advances, there is no cure for HIV nor a preventive HIV vaccine. This article summarises the recent IUIS-Immunopaedia-Frontiers in Immunology webinar featuring Professor Lynn Morris biomedical scientist* at the National Institute for Communicable Diseases (NICD) South Africa who focused on HIV prevention: antibodies and vaccine development.
- (i) RV144 (ALVAC. And AIDSVAC vaccine) trial that demonstrated a 31% efficacy against the acquisition of infection and demonstrated that non-neutralising Abs correlated against the reduced risk of infection
- (ii) HVTN702 trial (similar vaccine as the one tested in the RV144 trials, however, vaccines were modified to clades that are dominant in Sub-Saharan Africa) which was, unfortunately, stopped early due to similar infection rates in vaccine and placebo group.
- (iii) HVTN705/706 efficacy trial of Ad26.Mos4.HV and Clade C gp140 HIV vaccines were designed to induce non-neutralising Abs and showed good protection in non-human primates (results expected in 2022/3)
The ultimate aim of the HIV vaccine field is to induce broadly neutralising Abs (bNAbs). Unfortunately, bNAbs take years to develop and may not happen in all individuals, thus a key focus is to understand immunological processes associated with bNAb development with the hope of inducing a similar response using vaccination. New bNAb vaccine concepts are currently in phase 1 clinical trial testing and include
- (i) Germline Targeting approach is designed to stimulate rare B cells that give rise to Abs that bind the CD4 HIV binding site.
- (ii) Trimer Immunisations with soluble versions of the HIV glycoprotein.
- (iii) Fusion peptide priming
- (iv) Sequential and slow delivery immunisation priming and boosting immunity
Prof Morris ended this section of her talk by highlighting how the Moderna vaccine was initially designed for HIV, and how the HIV field is investigating the potential for mRNA based HIV vaccines.
In the next summary, we shall highlight discussion points focused on passive immunisation and findings from the Antibody-Mediated Prevention (AMP) trial.
*Director of the Antibody Immunity Research Unit at the University of the Witwatersrand. Over the last 20 years Lynn has made significant contributions to understanding the antibody response to HIV infection and co-discovered the CAP256-VRC26.25 monoclonal antibody that is undergoing clinical testing for HIV prevention. Her laboratory performs neutralizing antibody assays for HIV vaccine trials and played a key role in the proof-of-concept Antibody Mediated Prevention (AMP) trial.