This image shows an organ of the immune system in the process of responding to a new type of HIV vaccine. The cyan/green color is the vaccine, and the red indicates cells that collect information for further use. The blue color are the cells that are in the process of making antibodies that attach to the vaccine.

Lymph nodes are the organs in which the immune system gathers information to train itself to defend the body against pathogens. We’re trying to get our HIV vaccine components to the right regions and cell types within lymph nodes so that the immune system can develop a stronger response.