Basic research in HIV vaccinology is hampered by reductionist thinking
- Stellenbosch Institute of Advanced Study, Wallenberg Research Center at Stellenbosch University, Stellenbosch, South Africa
This review describes the structure-based reverse vaccinology approach aimed at developing vaccine immunogens capable of inducing antibodies that broadly neutralize HIV-1. Some basic principles of protein immunochemistry are reviewed and the implications of the extensive polyspecificity of antibodies for vaccine development are underlined. Although it is natural for investigators to want to know the cause of an effective immunological intervention, the classic notion of causality is shown to have little explanatory value for a system as complex as the immune system, where any observed effect always results from many interactions between a large number of components. Causal explanations are reductive because a single factor is singled out for attention and given undue explanatory weight on its own. Other examples of the negative impact of reductionist thinking on HIV vaccine development are discussed. These include (1) the failure to distinguish between the chemical nature of antigenicity and the biological nature of immunogenicity, (2) the belief that when an HIV-1 epitope is reconstructed by rational design to better fit a neutralizing monoclonal antibody (nMab), this will produce an immunogen able to elicit Abs with the same neutralizing capacity as the Ab used as template for designing the antigen, and (3) the belief that protection against infection can be analyzed at the level of individual molecular interactions although it has meaning only at the level of an entire organism. The numerous unsuccessful strategies that have been used to design HIV-1 vaccine immunogens are described and it is suggested that the convergence of so many negative experimental results justifies the conclusion that reverse vaccinology is unlikely to lead to the development of a preventive HIV-1 vaccine. Immune correlates of protection in vaccines have not yet been identified because this will become feasible only retrospectively once an effective vaccine exists. The finding that extensive antibody affinity maturation is needed to obtain mature anti-HIV-1 Abs endowed with a broad neutralizing capacity explains why antigens designed to fit matured Mabs are not effective vaccine immunogens since these are administered to naive recipients who possess only B-cell receptors corresponding to the germline version of the matured Abs.
Keywords: antibody affinity maturation, antibody polyspecificity, discontinuous protein epitopes, HIV vaccines, rational vaccine design, reductionism, reverse vaccinology, systems biology
Citation: Van Regenmortel MHV (2012) Basic research in HIV vaccinology is hampered by reductionist thinking. Front. Immun. 3:194. doi: 10.3389/fimmu.2012.00194
Received: 27 April 2012; Accepted: 21 June 2012;
Published online: 09 July 2012.
Copyright: © 2012 Van Regenmortel. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
*Correspondence:Marc H. V. Van Regenmortel, CNRS, UMR7242 – Institut de Recherche de l’Ecole de Biotechnologie de Strasbourg, Université de Strasbourg, Illkirch 67400, France. e-mail: email@example.com