This paper is highly cited because it is one of the first to demonstrate that single stranded RNA viruses are recognized via a Toll-like receptor, TLR7.

It describes a new discovery that is useful to others interested in how viruses are detected by the host innate immune system.

We demonstrated the critical requirement for a receptor in detecting a class of viruses that use single-stranded RNA as their genomes. This requirement applies to a particular white blood cell type known as the plasmacytoid dendritic cells, which are specialized in detecting a variety of viruses and providing antiviral factors, such as the type I interferons to suppress the spread of the infection in the host animal.

In an attempt to clarify what the biological role of the different TLRs in the induction of immune responses in mammals is, we have generated a series of gene-targeted TLR-deficient mice in the laboratory of Richard Flavell at Yale University School of Medicine. TLR7-deficient mice were one of them. On the other hand, the major focus of the Mucosal Dendritic Cell Laboratory of Akiko Iwasaki at Yale is to understand how viruses are detected by the host innate immune system. We had some clues that TLR7 is involved in the recognition of viral single-stranded RNA and by putting together our expertise and tools we were able to clearly show that TLR7 is utilized by the plasmacytoid dendritic cells in detecting single-stranded RNA viruses.