The role of carbohydrate in determining the immunochemical properties of the hemagglutinin of influenza A virus

Abstract

Most of the carbohydrate was removed from influenza virus MRC II (H3N2) and its purified hemagglutinin (HA) on treatment with glycosidases, including alpha-mannosidase, beta-N-acetylglucosaminidase, beta-galactosidase and alpha-fucosidase. The release of 50 per cent of the carbohydrate from intact virus particles significantly affected hemagglutinating activity. The ability of untreated and glycosidase-treated virus to inhibit the binding of antibodies directed against the hemagglutinin was almost indistinguishable by competitive radioimmunoassay (RIA). Up to 60 per cent of the carbohydrate from the purified HA of influenza virus could be removed. The antigenicity of glycosidase treated HA molecules decreased 8-fold compared to intact HAs as measured by competitive RIA. In addition, glycosidase digestion of 125I-labeled HA resulted in a decrease in its reactivity in direct RIA. We conclude that the carbohydrate portion of the HA of influenza virus is not of major importance in defining the antigenicity of HA.

Role of N-linked glycans in the interaction between the envelope glycoprotein of human immunodeficiency virus and its CD4 cellular receptor. Structural enzymatic analysis.

“…Carbohydrate moieties of glycoproteins are known to play different roles in intracellular routing (6), protection of the molecule against proteolytic degradation (7), governing correct folding and stabilizing bioactive conformation of the molecule (7), or as epitopes for antibody immune responses (8,9). Carbohydrates are also involved in the regulation of molecular metabolism (10)(11)(12), growth and differentiation (11,13), and in cell-to-cell adhesion (14,15).…”

Demonstration and Mapping of Highly Carbohydrate-dependent Epitopes in the Herpes Simplex Virus Type 1-Specified Glycoprotein C

“…So far, these epitopes seem to be unique among viral glycoproteins as their reactivity is lost after treatments removing only a small fraction of the carbohydrate content. Carbohydrate-dependent epitopes have been demonstrated previously for glycoproteins of other viruses such as Newcastle disease virus (Merz et al, 1981, Long et al, 1986, Semliki Forest virus (Kaluza et al, 1980) and influenza virus (Gitelman et al, 1981;Hongo et al, 1986). However, the carbohydrate dependence of these epitopes was detected in glycoprotein produced in the presence of tunicamycin, resulting in a completely non-glycosylated protein (Long et at., 1986;Kaluza et al, 1980) or in extensively glycosidase-treated glycoproteins (Gitelman et al, 1981).…”

The functions of oligosaccharide chains associated with influenza C viral glycoproteins

“…GIWSr,MA~ et al (7) have analysed the antigenicity of influenza A virM HA proteins by competitive radioimmunoassay before and after glycosidase treatment, and have demonstrated a significant decrease in the antigenicity of HA after removal of more than 50 per cent of carbohydrates. Immunopreeipitation experiments revealed that of the three monoclonal antibodies tested, two antibodies designated S-i6 and J-6 reacted with both the gp 88 and T 76 polypeptides, indicating that some of the antigenic determinants on gp88 molecules can be expressed even in the absence of gtycosylation.…”

“…It has been reported that the antigenicity of either gp71 of Friend marine leukemia virus or gp85 of avian sarcoma virus (B77) remained intact even after the removal of most carbohydrates by digestion with a mixture of highly purified glycosidases (22,26). G[TELMAN et al (7) have also demonstrated that the antigenicity of influenza A viral hemagglutinin (HA) was significantly reduced after glycosidase treatment. G[TELMAN et al (7) have also demonstrated that the antigenicity of influenza A viral hemagglutinin (HA) was significantly reduced after glycosidase treatment.…”