Virgin queens of the honey bee Apis mellifera L. were assessed following feeding in fourth larval instar with a sublethal dose of bacterium Paenibacillus larvae larvae (LD20 = 1.07 × 10² colony forming units (CFU)/queen), the causative agent of American foulbrood disease (AFB). The extraction of ovary proteins showed a highly significant increase for treated queens. The bacterium P. l. larvae was detected by conventional PCR-technique within treated queens ovaries with molecular size of 550 bp. Vitellogenin gene has been expressed in healthy and treated queens using RT-PCR technique, up-regulation took place in treated queens, vitellogenin was found with a high level of gene expression (∼20-fold). Finally, this study could contribute to initial efforts to help attempts to breed honey bee queens that are resistant to the pathogen.