The role of complement in the tick cellular immune defense against the entomopathogenic fungus Metarhizium robertsii
Dev Comp Immunol. 2021 Aug 24:104234. doi: 10.1016/j.dci.2021.104234. Online ahead of print.ABSTRACTEntomopathogenic fungi (EPF) have been widely explored for their potential in the biological control of insect pests and as an environmentally friendly alternative to acaricides for limiting tick infestation in the field. The arthropod cuticle is the main barrier against fungal infection, however, an understanding of internal defense mechanisms after EPF intrusion into the invertebrate hemocoel is still rather limited. Using an infection model of the European Lyme borreliosis vector Ixodes ricinus with the EPF Metarhizium robertsii, we demonstrated that ticks are capable of protecting themselves to a certain extent against mild fungal infections. However, tick mortality dramatically increases when the capability of tick hemocytes to phagocytose fungal conidia is impaired. Using RNAi-mediated silencing of tick thioester-containing proteins (TEPs), followed by in vitro and/or in vivo phagocytic assays, we found that C3-like complement components and α2-macroglobulin pan-protease inhibitors secreted to the hemolymph play pivotal roles in M. robertsii phagocytosis.PMID:34450130 | DOI:10.1016/j.dci.2021.104234
Am Fam Physician. 2021 Dec 1;104(6):589-597.ABSTRACTSeptic arthritis must be considered and promptly diagnosed in any patient presenting with acute atraumatic joint pain, swelling, and fever. Risk factors for septic arthritis include age older than 80 years, diabetes mellitus, rheumatoid arthritis, recent joint surgery, hip or knee prosthesis, skin infection, and immunosuppressive medication use. A delay in diagnosis and treatment can result in permanent morbidity and mortality. Physical examination findings and serum markers, including erythrocyte sedimentation rate and C-reactive protein, are helpful in the diagnosis but...