EN
The paper characterizes and discusses the immune response mechanisms of the honey bee, mainly bee larvae, to infection caused by Paenibacillus larvae, the absolute pathogen of honey bee larvae. A statistically significant increase in abaecin was found in the youngest larvae during 24 h after infection that is during the germination of P. larvae endospores and the penetration of vegetative cells into the gut epithelium. Moreover, P. larvae stimulate the production of defensin - an immune protein of bee larvae. The comparative analysis of social insects and solitary model insects Drosophila melanogaster and the mosquito Anopheles gambiae revealed a significant differentiation in the number of genes and their products that play a significant role in insects’ protection against microorganisms. The comparison of the number of genes responsible for three stages of immune defense: recognition of foreignness, information transfer and effector activity showed 71 genes in the honey bee, but 209 and 196 genes in the Anopheles gambiae and Drosophila melanogaster, respectively. These tremendous differences in the number of immune genes between the discussed representatives of insects could be explained by the development of behavioral protective mechanisms in the honey bee, and probably also by the limited number of honey bee pathogens.