Antigen Unit

Abstract: With the development of methods for the effective separation of the strain-specific virus (V) antigen from the broader reacting type-specific soluble (S) antigen and the production of sera containing antibodies to either one or the other of these antigens, it has become possible to demonstrate strain-specific components of influenza viruses by complement fixation Data are presented on the application of strain-specific anti-V sera, free of anti-S, prepared against a variety of strains, to the identification and strain analysis of new isolates The procedures used for definitive diagnosis depended upon whether the isolate was a member of a recognized family of strains, as A prime, or a totally new variant as represented by the Asian strains Thus, three influenza viruses obtained from outbreaks which occurred in February 1957, on a preliminary screening test, were found to fix complement in the presence of several A prime antisera, but not with antisera against swine 15 or five prototype A strains On titrating the cross-reacting antisera versus the new isolates, the results indicated that all three viruses were closely related to the Nederland 36 strain isolated in 1956 They were distinguishable from one another and from Nederland 36, however, by the spectrum and level of the cross-reactions with other A prime strains Assay of antisera prepared against the new isolates further clarified their antigenic composition When the Asian variant appeared, the identification of isolates could be restricted to the screening test since no cross-reactions were readily detectable with antisera against any of the earlier strains Positive complement fixation occurred solely with the A/Japan/305 antiserum Identification was carried out by testing aliquots of infected allantoic fluid, which contained at least 16 HA units, the equivalent of one V antigen unit, against a battery of anti-V sera diluted optimally in respect to their homologous reactions In this fashion, early passage material containing as little as 40 HA units/ml could be identified, if 05 ml were used for testing Thus, of 51 viruses obtained from throat washings 80% were diagnosed on first passage The implications of the use of the technique are discussed

Abstract: Honeybees (Apis mellifera) produce unique complex-type N-glycans bearing a Galβ1-3GalNAc (T-antigen) unit, and honeybee-specific N-glycans are linked to royal jelly glycoproteins. In this study, we identified two novel honeybee β1,3-galactosyltransferase (β1,3-GalT) genes responsible for biosynthesis of the T-antigen in insect N-glycans. The products of the two putative β1,3-GalT genes (β1,3-GalT1 and β1,3-GalT2), which were expressed in Sf21 insect cells, transferred galactose (Gal) residues to GalNAc2GlcNAc2Man3GlcNAc2-PA to form the Galβ1-3GalNAc unit, indicating that the identified genes were involved in biosynthesis of the β1-3 Gal-containing N-glycan. Therefore, using biochemistry and molecular biology techniques, we revealed a unique N-glycan biosynthesis mechanism in the cephalic region of honeybees, which has not previously been found in other animal or plant cells.