Despite being of central relevance for understanding bat-related diseases, surprisingly little is known about bat immunology and how bat immune responses engage pathogenic and non-pathogenic micro-organisms and parasites. This is principally because of a historical lack of appreciation of pathogens that cause diseases in bats and the role of bats as reservoirs of zoonotic disease agents. Since bat species have been increasingly identified as reservoirs for many diseases affecting humans, and because of the emergence of WNS, a concerted effort has been made by researchers to address these deficiencies, some of which were reported at the meeting.
Genetic studies presented at the meeting identified orthologous bat immune genes, including major histocompatibility class II genes and multiple alleles in Eptesicus fuscus and Noctilio albiventris. Data suggested that certain alleles may be associated with parasite burden. Innate, antiviral and interferon genes from Pteropus alecto, P. vampyrus and M. lucifugus have also been identified. Most Toll-like receptors orthologues involved in microbial pattern recognition have been detected in Pteropus genome scans by Baker (CSIRO Livestock Industries, Australia) and co-workers. Speakers agreed that specific assays for immunoglobulin subtypes are needed, particularly in the light of the study by James Aegerter (FERA, UK) and co-workers who demonstrated the potential use of an IgA detection assay that may be helpful in characterizing mucosal antibody responses. Functional assays also demonstrated bactericidal and fungicidal activity of complement from M. lucifugus (Moore and co-workers, Boston University, USA) and E. fuscus (Warburton and Vonhof, Western Michigan University, USA), as well as T-cell assays assessing delayed-type hypersensitivity, and plasma hormonal modulation in Carollia perspicillata (Greiner and co-workers, IZW, Germany). Efforts from Hjalmar Bouma and co-workers (University of Groningen, The Netherlands) found reduction of neutrophils, monocytes and lymphocytes in torpid hamsters (Mesocricetus auratus), a finding that may have relevance to immunocompetence in torpid bats, particularly for those affected by WNS.