The effect of cold shock on the immune response of thegreater wax moth Galleria mellonella after infection withentomopathogenic bacteria Bacillus thuringiensis

Insect immune system consists of only innate mechanisms relied on cellular and humoralbranches. Many defence proteins and peptides exist or appear in response to infection in insect shemolymph. The interaction between the infected host and the entomopathogen occurs in theconditions of external environment. In this work the greater wax moth larvae of Galleria mellonellawere subjected to a temperature of 12°C for a short period of time, directly before infection withentomopathogenic bacteria Bacillus thuringiensis. It appeared that the induction of the immuneresponse was higher in cold-shocked animals than in larvae permanently reared at the optimaltemperature of 28 °C. This enhanced immune response was manifested as higher antibacterial andlysozyme-type activity detected in full hemolymph, and as a higher level of peptides of molecularweight below 10 kDa having antibacterial activity. Moreover, other changes in the contents ofproteins in the hemolymph were observed. These changes concerned inter alia apolipophorin III, themultifunctional protein of immune significance. Its level was higher in the hemolymph of animalspre-exposed to cold shock than in nonshocked, infected ones. Altogether our results indicate that theinterdependence mechanisms occur between cold shock and the immune response.