INFLUENCE OF PARENT SELECTION METHODS BY B ANTIGEN SIMILARITY INDEX IN THE BLOOD GROUPS ON WEIGHT AND LINEAR GROWTH OF BULLS

In solving the problem of qualitative improvement of beef breeds, it is important to improve the methods of practical use of existing parent couples selection methods, using histocompatibility antigens, polymorphic proteins and blood group systems. The purpose of the thesis is to determine the influence of homogeneous and heterogeneous selection of parent couples by blood group factors on the weight and linear growth of bulls of Ukrainian beef breed. The Ukrainian beef breed was bred using four breeds and is characterized by high variability in polymorphic features. The type of parent selection was determined by the index of B antigen similarity (ras) of cattle blood groups. The formula of D.A. Zhyvotovskyi and A.M. Mashurov was used to calculate the index of antigenic similarity of parents. Selection by ras of parents ≥ 0,268 was considered homogeneous, and by ras ≤ 0,267 heterogeneous. It has been proven that bulls that are descended from their parents with more ras pravail in the test on average daily gains and have a higher live weight. If ras of the parents is over 0.268, animals tend to improve their growth rate up to 8 months of age. After weaning this trend persists. The average daily gain of bulls obtained from parents with ras up to 0.267 is better in the period from 15 to 18 months, which indicates their lower precocity. If the antigenic similarity index of parents is more than 0.268, the animals are better in terms of the severity of meat forms at the age of 15 and 18 months. At the age of 15 months, bulls obtained from homogeneous selection by ras have smaller height measurements, better developed front of the torso in width and depth of the chest, longer torso and buttocks. Homogeneous selection of parental couples according to the B antigen similarity index of blood groups leads to improvement of weight growth and severity of meat forms of bulls of Ukrainian beef breed.

Antigenic distance between North American swine and human seasonal H3N2 influenza A viruses as an indication of zoonotic risk to humans

Human-to-swine transmission of influenza A virus (IAV) repeatedly occurs, leading to sustained transmission and increased diversity in swine; human seasonal H3N2 introductions occurred in the 1990s and 2010s and were maintained in North American swine. Swine H3N2 were subsequently associated with zoonotic infections, highlighting the need to understand the risk of endemic swine IAV to humans. We quantified antigenic distances between swine H3N2 and human seasonal vaccine strains from 1973 to 2014 using a panel of monovalent antisera raised in pigs in hemagglutination inhibition (HI) assays. Swine H3N2 lineages retained closest antigenic similarity to human vaccine strains from the decade of incursion. Swine lineages from the 1990s were antigenically more similar to human vaccine strains of the mid-1990s but had substantial distance from recent human vaccine strains. In contrast, lineages from the 2010s were closer to human vaccine strains from 2011 and 2014 and most antigenically distant from human vaccine strains prior to 2007. HI assays using ferret antisera demonstrated that swine lineages from the 1990s and 2010s had significant fold-reduction compared with the homologous HI titer of the nearest pandemic preparedness candidate vaccine virus (CVV) or seasonal vaccine strain. The assessment of post-infection and post-vaccination human sera cohorts demonstrated limited cross-reactivity to swine H3N2 from the 1990s, especially in older adults born before 1970s. We identified swine strains to which humans are likely to lack population immunity or are not protected against by a current human seasonal vaccine or CVV to use in prioritizing future human CVV strain selection. IMPORTANCE Human H3N2 influenza A viruses spread to pigs in North America in the 1990s and more recently in the 2010s. These cross-species events led to sustained circulation and increased H3N2 diversity in pig populations. Evolution of H3N2 in swine led to a reduced similarity with human seasonal H3N2 and the vaccine strains used to protect human populations. We quantified the antigenic phenotypes and found that North American swine H3N2 lineages retained more antigenic similarity to historical human vaccine strains from the decade of incursion but had substantial difference compared with recent human vaccine strains. Additionally, pandemic preparedness vaccine strains demonstrated a loss in similarity with contemporary swine strains. Lastly, human sera revealed that although these adults had antibodies against human H3N2 strains, many had limited immunity to swine H3N2, especially older adults born before 1970. Antigenic assessment of swine H3N2 provides critical information for pandemic preparedness and candidate vaccine development.

Retrospective Assessment of the Antigenic Similarity of Egg-Propagated and Cell Culture-Propagated Reference Influenza Viruses as Compared with Circulating Viruses across Influenza Seasons 2002–2003 to 2017–2018

Suboptimal vaccine effectiveness against seasonal influenza is a significant public health concern, partly explained by antigenic differences between vaccine viruses and viruses circulating in the environment. Haemagglutinin mutations within vaccine viruses acquired during serial passage in eggs have been identified as a source of antigenic variation between vaccine and circulating viruses. This study retrospectively compared the antigenic similarity of circulating influenza isolates with egg- and cell-propagated reference viruses to assess any observable trends over a 16-year period. Using annual and interim reports published by the Worldwide Influenza Centre, London, for the 2002–2003 to 2017–2018 influenza seasons, we assessed the proportions of circulating viruses which showed antigenic similarity to reference viruses by season. Egg-propagated reference viruses were well matched against circulating viruses for A/H1N1 and B/Yamagata. However, A/H3N2 and B/Victoria cell-propagated reference viruses appeared to be more antigenically similar to circulating A/H3N2 and B/Victoria viruses than egg-propagated reference viruses. These data support the possibility that A/H3N2 and B/Victoria viruses are relatively more prone to egg-adaptive mutation. Cell-propagated A/H3N2 and B/Victoria reference viruses were more antigenically similar to circulating A/H3N2 and B/Victoria viruses over a 16-year period than were egg-propagated reference viruses.

2556. Retrospective Evaluation of Mismatch From Egg-Based Isolation of Influenza Strains Compared With Cell-Based Isolation and the Possible Implications for Vaccine Effectiveness

Background Lower influenza vaccine effectiveness (VE) against circulating H3N2 strains compared with other influenza viruses is partly explained by antigenic mismatch between circulating strains and the vaccine strain (Belongia 2016). This mismatch has recently been linked to a new glycosylation site introduced in the egg-adaptation step (Zost 2017) and HA L194P substitution (Wu 2017) for H3N2. Vaccine manufactured using seed virus wholly grown in mammalian (e.g., Madin–Darby Canine Kidney—MDCK) cells, as with the NH17-18 version of Flucelvax®, avoids these mutations. Preliminary reports suggest that this cell-based vaccine showed greater VE than did similar egg-based vaccines [FDA Statement]. This study aimed to compile existing data on antigenic similarity to measure the degree of match with circulating wild-type isolates of egg- and MDCK-propagated versions of the vaccine H3N2 virus over multiple seasons. Methods Using publicly available reports from the Worldwide Influenza Centre, London (Crick), we compiled data on antigenic similarity, defined as H3N2 circulating wild-type virus isolates showing no more than a 4-fold reduction in titer to antisera raised against wholly MDCK- or egg-propagated versions of the vaccine H3N2 viruses. Titers were compared using hemagglutination inhibition (HI) assays and/or plaque reduction neutralization assays (PRNA). Results Data from Northern Hemisphere influenza seasons of 2011–2012 to 2017–2018 show a substantially higher proportion of tested circulating influenza H3N2 viruses matched the MDCK-propagated reference viruses than did corresponding egg-propagated reference vaccine viruses (Figures 1 and 2). In half of the seasons evaluated, there was little to no antigenic similarity between circulating viruses and the egg-based vaccine viral seed. Conclusion These data suggest higher levels of mismatch have occurred consistently with egg-propagated H3N2 reference viruses compared with MDCK-propagated reference viruses when measured against circulating wild-type isolates and may further explain the potential for lower VE observed against H3N2 historically. Furthermore, these data point to the importance of continuing to utilize cell-derived seeds in creating seasonal influenza vaccines for this strain. Disclosures S. Rajaram, Seqirus: Employee, Salary. J. Van Boxmeer, Seqirus: Employee, Salary. B. Leav, Seqirus: Employee and Shareholder, Salary. P. Suphaphiphat, Seqirus: Employee, Salary. I. Iheanacho, Seqirus: Consultant, Research support. K. Kistler, Seqirus: Consultant, Research support.

Comparison of serological assays in human Middle East respiratory syndrome (MERS)-coronavirus infection

Plaque reduction neutralisation tests (PRNT), microneutralisation (MN), Middle East respiratory syndrome (MERS)-spike pseudoparticle neutralisation (ppNT) and MERS S1-enzyme-linked immunosorbent assay (ELISA) antibody titres were compared using 95 sera from 17 patients with MERS, collected two to 46 days after symptom onset. Neutralisation tests correlated well with each other and moderately well with S1 ELISA. Moreover to compare antigenic similarity of genetically diverse MERS-CoV clades, the response of four sera from two patients sampled at two time periods during the course of illness were tested by 90% PRNT. Genetically diverse MERS-CoV clades were antigenically homogenous.

Studies on antigenic differences in needle proteins of Pinus sylvestris L., P. mugo Turra, P. uliginosa Neumann and P. nigra Arnold

By means of serological methods (double immunodiffusion, immunoabsortion and quantitative immunoprecipitation), using three kinds of antisera: antisylvestris, antimugo and antiuliginosa authors performed a comparison of antigenic properties of proteins from needles of <i>P. sylvestris, P. mugo, P. uliginosa</i> and <i>P. nigra</i>. Proteins characteristic for the species <i>P. sylvesiris</i>, and <i>P. uliginosa</i> were found. On the basis of the results obtained it was established, that the most distinct species are <i>P. mugo</i> and <i>P. sylvestris, P. uliginosa</i> is antigenically different from the two taxa but is showing greater similarity to <i>P. mugo</i> than to <i>P. sylvestris. P. nigra</i> proteins are different from proteins <i>P. sylvestris, P. mugo</i>, and <i>P. uliginosa</i>. They show however, some antigenic similarity to <i>P. sylvestris</i> proteins.