Immunology Studies. The complex issue of immunology continues to attract the attention of a large number of our readers. This issue opens with six papers on this subject. Starting on page 397 is the report of a laboratory study using vaccinia virus recombinants that were constructed incorporating genomic sequences from a strain of hantavirus isolated from China. One of the expressed proteins was found to induce a protective immune response in Mongolian gerbils when challenged with the original virus as well as an additional serotype of this viral group. The authors conclude that the antigenic sites associated with protective responses are located mainly on hantavirus glycoproteins. Envelope structural proteins from dengue-2 virus purified by high-pressure liquid chromatography have been found to maintain their reactivity with monoclonal antibodies and to elicit neutralizing antibodies that partially protected mice against what would normally have been a lethal challenge.