Around 37 million people worldwide are infected with HIV, the human immunodeficiency virus. There are now effective therapies, but there still is no cure or vaccination against HIV/AIDS. About 1 % of all HIV-infected people produce special antibodies. Not only are these antibodies directed against a virus strain, but they also work against most circulating strains of the world and may, therefore, be the key to an effective vaccine. They are called broadly neutralizing antibodies (bNAbs).

Roger D. Kouyos, Huldrych F. Günthard, Alexandra Trkola, University of Zurich, Switzerland, and colleagues have researched which factors are crucial for the production of these broad-spectrum antibodies. For example, the amount and variety of viruses, the duration of the infection, or the ethnicity of the affected person can affect the immune response. The team has identified another important factor: the gene sequence of the HI virus.

The HI virus itself has an influence on the amount and specificity of the antibody reaction. Crucial in this context are, in particular, the envelope proteins of the particular pathogen. These proteins on the virus surface form the target for antibodies and differ depending on the virus strain and subtype.

The scientists examined blood and virus samples from around 4,500 people infected with HIV. They came across 303 potential transmission pairs—pairs of patients who had highly related HIV strains with very similar viral RNA. In one pair of patients, the researchers found circulating viruses which produced a very strong bNAb activity. Based on these results, the team intends to start developing an immunogen in the future. The researchers will also search for additional viruses with promising envelope proteins.

• Tracing HIV-1 strains that imprint broadly neutralizing antibody responses,
  Roger D. Kouyos, Peter Rusert, Claus Kadelka, Michael Huber, Alex Marzel, Hanna Ebner, Merle Schanz, Thomas Liechti, Nikolas Friedrich, Dominique L. Braun, Alexandra U. Scherrer, Jacqueline Weber, Therese Uhr, Nicolas S. Baumann, Christine Leemann, Herbert Kuster, Jean-Philippe Chave, Matthias Cavassini, Enos Bernasconi, Matthias Hoffmann, Alexandra Calmy, Manuel Battegay, Andri Rauch, Sabine Yerly, Vincent Aubert, Thomas Klimkait, Jürg Böni, Karin J. Metzner, Huldrych F. Günthard, Alexandra Trkola,
  Nature 2018.
  https://doi.org/10.1038/s41586-018-0517-0