Objective To prepare and characterize specific monoclonal antibodies( McAbs) against the heavy chain of botulinum neurotoxin serotype A ( BoNT/AHc ) .Methods BALB/c mice were immunized with purified BoNT/AHc protein.After the fusion of mouse splenic cells with SP2/0 cells, hybridoma cell lines secreted McAbs against BoNT/AHc. The McAbs obtained were characterized by indirect ELISA, Western blotting and rapid isotypingassay before being used in ELISA to detect interaction sites in McAbs and BoNT/AHc preliminarily.Results Antigen protein BoNT/AHc of high purification was obtained.Four hybridoma cell lines secreting McAbs against BoNT/AHc were screened,named 1A4,3H3, 3H7 and 5H8,respectively.Their titers of McAbs were all above 3.0 ×103 .They were specifically combined with BoNT/AHc protein by Western blotting.The isotype of 1A4 and 3H7 was IgG1(Κ),that of 3H3 was IgM(Κ),and that of 5H8 was IgG2b(Κ).Additive ELISA showed that epitopes recognized by the four McAbs were close.ELISA analysis confirmed the interaction epitopes in McAbs and BoNT/AHc.Conclusion Monoclonal antibodies against BoNT/AHc are prepared and characterized,providing effective tools for studying the neutralizing antibody and antibody epitopes of BoNT/AHc.

Objective To analyze the epidemiological characteristics of mumps in Guangxi from 2011 to 2019, and to provide a scientific basis for formulating effective prevention and control strategies. Methods Descriptive epidemiological method was used to analyze the incidence data of mumps in Guangxi from 2011 to 2019. Results From 2011 to 2019, a total of 146,132 cases of mumps were reported in Guangxi, with an average annual incidence rate of 34.23 /100 000. There were 88,919 male cases (60.85%) and 57,213 female cases (39.15%). The incidence rate decreased from 62.26/100 000 in 2011 to 16.46/100 000 in 2015, and increased from 18.60/100 000 in 2016 to 46.90/100 000 in 2019. There were seasonal variations in the incidence, with the incidence peaks occurring from April to July and from October to the following January. 85.39% of cases were under 15 years of age, and 76.82% of cases were among kindergarteners or school children. A total of 228 mumps outbreaks were reported during 2011-2019，including 5,347 cases, accounting for 3.66% of the total cases. The incidence rates of mumps in Nanning (56.09/100 000), Hechi (48.26/100 000), Liuzhou (46.77/100 000), Baise (46.34/100 000) and Fangchenggang (40.68/100,000) were relatively higher than other places. Conclusion The mumps incidence is on an upward trend in Guangxi since 2015-2019, occurring mainly in older children or students. It is suggested to adhere to the second dose of mumps containing vaccine for kindergarten and school children and strengthen the surveillance and outbreak control of mumps in schools.