Until recently, no one has identified an immunogen capable of eliciting broadly neutralizing antibodies (Bnabs) to HIV in either human or animal models. However, a 2017 National Institute of Allergy and Infectious Diseases (NIAID) research initiative has immunized four cows with the soluble cleaved trimer BG505 SOSIP in an attempt to produce these Bnabs – and has succeeded.
Since antibodies in cows are approximately 4 to 5 times longer than typical human antibodies, the cows antibodies have a greater chance of penetrating the sugars surrounding the HIV virus and neutralizing it. There is not yet a clear path to achieving the same results in humans, but according to the director of vaccine research at the NIAID, John Mascola, MD, while the study “doesn’t tell us how to make a vaccine for HIV in human patients [...] it does tell us how the virus evades the human immune response.”
Sok, Devin, et al. Rapid elicitation of broadly neutralizing antibodies to HIV by immunization in cows. Nature. Available at: http://www.nature.com/nature/journal/v548/n7665/full/nature23301.html.