Funding: the study was supported by the Ministry of Science and Higher Education of the Russian Federation (agreement № 075-15-2021-1086, contract № RF––193021X0015).

Acknowledgements: the authors thank M.V. Rutovskaya, Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, for assistance in immunization of the camel.

Author contribution: Vorobyev PO — molecular cloning and subsequent production of recombinant proteins (antigens for immunization); Tillib SV — developing general conception, carrying out immunization, developing the method for acquisition and primary analysis of the generated single-domain antibodies, manuscript writing.

Compliance with ethical standards: the study was approved by the Ethics Committee of the Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (protocol № 17 of 11 February 2018); the animal was handled in strict compiance with the guidelines of the National Standard of the Russian Federation GOST R 53434–2009.