Antibody Dynamic Changes in SPF Chickens and SPF Ducks Immuned with Recombinant Avian Influenza Virus H5 Subtype Bivalent Inactivated Vaccine

To study the immune effect of recombinant avian influenza virus H5 subtype bivalent inactivated vaccine （ HSN1, Re-6 strain ＋ Re-4 strain） and to provide the basis for formulating reasonable immune procedure of avian influenza vaccine in clinical practice. A total of 12 batches of vaccines from three companies were used for the iannune of SPF chickens and SPF ducks. Each chicken or duck serum was separately collected every 3 weeks until the immunization up to the 24^th week. The serum antibody titers of Re-6 and Re-4 were detected. The results showed that the HI titers of the inoculated SPF chickens and SPF ducks roached the peak when the immune time were the 6^th and 3^rd week after the first immunization respectively; then the titer decreased gradually as time prolonged; the highest titer of SPF chickens was greater than that of SPF ducks; the high titer duration of SPF chickens were longer than that of SPF ducks ; and all the vaccines from the three companies showed a good immune effect.

An agent-based model with antibody dynamics information in COVID-19 epidemic simulation

Accurate prediction of the temporal and spatial characteristics of COVID-19 infection is of paramount importance for effective epidemic prevention and control.In order to accomplish this objective,we incorporated individual antibody dynamics into an agent-based model and devised a methodology that encompasses the dynamic behaviors of each individual,thereby explicitly capturing the count and spatial distribution of infected individuals with varying symptoms at distinct time points.Our model also permits the evaluation of diverse prevention and control measures.Based on our findings,the widespread employment of nucleic acid testing and the implementation of quarantine measures for positive cases and their close contacts in China have yielded remarkable outcomes in curtailing a less transmissible yet more virulent strain;however,they may prove inadequate against highly transmissible and less virulent variants.Additionally,our model excels in its ability to trace back to the initial infected case(patient zero)through early epidemic patterns.Ultimately,our model extends the frontiers of traditional epidemiological simulation methodologies and offers an alternative approach to epidemic modeling.

Mild Cytokine Elevation, Moderate CD4^+ T Cell Response and Abundant Antibody Production in Children with COVID-19

Children with Coronavirus Disease 2019(COVID-19) were reported to show milder symptoms and better prognosis than their adult counterparts, but the difference of immune response against SARS-CoV-2 between children and adults hasn’t been reported. Therefore we initiated this study to figure out the features of immune response in children with COVID-19.Sera and whole blood cells from 19 children with COVID-19 during different phases after disease onset were collected.The cytokine concentrations, SARS-CoV-2 S-RBD or N-specific antibodies and T cell immune responses were detected respectively. In children with COVID-19, only 3 of 12 cytokines were increased in acute sera, including interferon(IFN)-cinduced protein 10(IP10), interleukin(IL)-10 and IL-16. We observed an increase in T helper(Th)-2 cells and a suppression in regulatory T cells(Treg) in patients during acute phase, but no significant response was found in the IFN-cproducing or tumor necrosis factor(TNF)-a-producing CD8?T cells in patients. S-RBD and N IgM showed an early induction, while S-RBD and N IgG were prominently induced later in convalescent phase. Potent S-RBD IgA response was observed but N IgA seemed to be inconspicuous. Children with COVID-19 displayed an immunophenotype that is less inflammatory than adults, including unremarkable cytokine elevation, moderate CD4?T cell response and inactive CD8?T cell response, but their humoral immunity against SARS-CoV-2 were as strong as adults. Our finding presented immunological characteristics of children with COVID-19 and might give some clues as to why children develop less severe disease than adults.