Antigen is a tool to help you to wrap an Ant scripts with a user-friendly GUI.
Suppose you have a nice Ant script for deploying your software. As a developer that's great, but your poor user might not have Ant installed on their machine, and even if they do, a text-based installation script isn't exactly friendly. Antigen will allow you to reuse your script, with all of Ant's power, and wrap it all up in a nice friendly GUI. The user doesn't need to install Ant, they just double-click on the executable jar file that Antigen creates.
Antibody is the java framework used in the installers. If the Antigen tool doesn't do what you want, then you can build the installers yourself by including the Antibody code. See the maven subprojects for examples. Why Antibody? I guess because Antigens give rise to Antibodies.
Ant Installer GENerator. I wanted InstAnt, but someone had already bagged that. Plus, it has more scope for sad puns.
A pollen grain. More of an allergen, but I guess it must be covered in antigens since the antihistamine industry is so profitable.