Antibacterial agents in innate immunity: comparison of vertebrates and invertebrates
| Title in English | Antibacterial agents in innate immunity: comparison of vertebrates and inv |
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| Authors | |
| Year of publication | 2011 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Innate immunity of both vertebrates and invertebrates contents number of antibacterial mechanisms. In invertebrates there is lysozyme and several different antibacterial peptides which are divided according to their stucture to four main groups called linear a-helical, cysteine-stabilized, proline-rich and glycine-rich inducible antimicrobial peptides. In vertebrates antibacterial components cooperate with antibodies, complement cascade and myeloperoxidase activity. Nowadays, many common methods for determination of non-specific innate immune parameters are known in vertebrates, nevertheless there is not so large variety of them in invertebrates. Therefore we tried to apply to invertebrates the bioluminescent bacteria-based assay which is commonly used for complement determination in vertebrates. Bioluminescent bacteria are frequent in salt water environment, but there is the only one genus of soil bacteria with natural bioluminescence – Photorhabdus sp. These symbiotic bacteria occur in the gut of entomopathogenic nematodes which are obligate insect parasites. Except of P. luminescens we used the artificial bioluminescent bacterium - genetically modified Escherichia coli K12 that carries Photorhabdus genes for bioluminescence. Bioluminescence is directly connected to the kinetics of bacterial viability. After addition of sample (silkworm or waxmoth haemolymph, fish or human plasma) we observed decrease in viability of bacteria expressed by reduced bioluminescent signal. Using different conditions of bioluminescence assay and inhibitors of particular immune effectors, we optimised this assay for antibacterial activity measurement of specific parts of immune system both in vertebrates and invertebrates. We found out that the level of antibacterial activity of complement in vertebrates is similar to the effect of antibacterial peptides in insect haemolymph. Moreover invertebrate immune system was in several reactions more effective than complement cascade in vertebrates. Our research is supported by grant from Grant Agency of Czech Republic (GA206/09/P470). |
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