The Unique Immune System of Bats: An Evolutionary Analysis and Bibliometric Study

Bats exhibit a greater capacity to tolerate diverse viruses than other terrestrial mammals. To address these questions, we utilized evolutionary and bibliometric analyses to explore the immunological characteristics of bats and identify contemporary research hotspots in bat immunity. To investigate the historical interactions between bats and viral infections, we used tBLASTn software to identify the integrated endogenous retroviruses within the genomes of nine bat species and seven other mammals. To elucidate the immune characteristics of bats, we used the OrthoFinder, CAFE, and Gene Ontology analyses to identify the phylogenetic trees and homologous genes, expanded/contracted gene families, and associated signaling pathways of 28 mammalian genomes. We also used a bibliometric analysis of the "immune system of bats" to identify research hotspots and deepen our understanding of the immune mechanisms in bats. Significant integrations of Gammaretroviruses, Spumaretroviruses, and Deltaretroviruses were observed within bat genomes. Notable expansions in gene families included Type III interferon, heat-shock protein 90 (HSP90), and members of the tumor necrosis factor receptor superfamily (TNFRSF). These expanded gene families are involved in signaling pathways related to "transcription and replication of influenza virus RNA," "COVID-19-related pathways," and "positive regulation of protein phosphorylation." Notable contractions were observed in the "type I interferon" and "antibody-related gene families." Bibliometric analysis further underscored the several significance of critical immune genes, such as HSP90, Type I interferon, Type III interferon, and TNF. The exploration of research hotspots revealed two predominant themes: "efficient and varied antiviral responses" and "dampened inflammation to prevent excessive inflammatory reactions," thereby elucidating the mechanisms underlying the immune adaptations of bats. Through the evolutionary and bibliometric analyses, we identified several critical immune genes and signaling pathways related to bat immunity. Currently, research on the immune system of bats primarily focuses on the themes of "efficient antiviral responses" and "inflammation suppression."