Bats (order Chiroptera) represent nearly one fifth of the approximately 5,000 known species of mammals, yet many aspects of their biology are poorly understood. Bats of certain species are well known reservoirs of Rabies virus but within the past few years bats have been identified as reservoirs or potential reservoirs of several important human and livestock pathogens. Among these are severe acute respiratory syndrome coronavirus, Nipah and Hendra paramyxoviruses, several lyssaviruses, and both Marburg virus and an ebolaviruses. In some instances, these viruses may cause persistent infection without recognizable pathology in the bat host. Even though these are medically important viruses, little is known as to how bat immune systems engage viruses or how these viruses evade a sterilizing host immune response. We are developing immunological methods for investigations of such studies in bats and have begun with one species, the Seba's Short-tailed Bat (Carollia perspicillata). We have successfully cloned and characterized partial cDNAs of four cytokine genes: tumor necrosis factor, interleukin-10 (IL-10), IL-23, and granulocyte macrophage stimulating factor. Our sequence analysis shows that these genes are highly conserved with regard to orthologous sequences. To our knowledge, these are the first cytokine genes cloned from bats of any species and are a first step in developing an immunological model for host:pathogen interactions in bats to assess gene expression in response to infections. We are currently in the early stages of experimental infections of bats with viruses to study the immunological basis of zoonotic persistence in bats.