title: Opposite immune reactivity of serum IgG and secretory IgA to conformational recombinant proteins mimicking V1/V2 domains of three different HIV type 1 subtypes depending on glycosylation.
abstract: The V1/V2 domain of the HIV-1 gp120 envelope protein has been shown to contribute to viral cell tropism during infection and also to viral recognition by neutralizing monoclonal antibodies. However, this domain has been poorly investigated. Carbohydrates have been demonstrated to dramatically influence immune reactivity of antisera to viral glycoprotein antigens. In this study, DNA sequences coding for V1/V2 domains from HIV-1 primary isolates of three subtypes (A, B, and C) were subcloned into a secretion vector and used to transfect CHO cells that are able to achieve the glycosylation of proteins. The structure of purified recombinant V1/V2 proteins was tested using two anti-V1/V2 monoclonal antibodies directed against either a linear or a conformational and glycosylation-dependent epitope (8.22.2 and 697-D). Serum or saliva of 14/82 seropositive patients with anti-V1/V2 reactivity demonstrated good recognition of the recombinant proteins. Deglycosylation of the recombinant proteins was found to increase the reactivity of the serum IgG to the clade A and C but not to clade B V1/V2 domain demonstrating that the recognition of glycosylation sites by serum IgG is clade dependent. When considering SIgA from parotid saliva, deglycosylation of all recombinant proteins tested decreased the reactivity, suggesting that glycosylation plays an important role in the recognition of V1/V2 domain target epitopes by this class of antibodies. In conclusion, these results suggest the influence of carbohydrate moieties on the specificity of the antibodies to the V1/V2 domain produced during HIV infection and the potential importance of viral glycans in vaccine responses after mucosal administration.
authors.affiliation: Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France.
authors.forename: Viviana
authors.initials: V
authors.lastname: Granados-Gonzalez
authors.forename: Julien
authors.initials: J
authors.lastname: Claret
authors.forename: Willy
authors.initials: W
authors.lastname: Berlier
authors.forename: Nadine
authors.initials: N
authors.lastname: Vincent
authors.forename: Silvio
authors.initials: S
authors.lastname: Urcuqui-Inchima
authors.forename: Frederic
authors.initials: F
authors.lastname: Lucht
authors.forename: Christiane
authors.initials: C
authors.lastname: Defontaine
authors.forename: Abraham
authors.initials: A
authors.lastname: Pinter
authors.forename: Christian
authors.initials: C
authors.lastname: Genin
authors.forename: Serge
authors.initials: S
authors.lastname: Riffard
mesh_terms: D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D018985:Epitopes, B-Lymphocyte / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006031:Glycosylation; D015699:HIV Envelope Protein gp120 / Q000276:immunology* / Q000378:metabolism; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000032:analysis / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000276:immunology; D012463:Saliva / Q000276:immunology; D016415:Sequence Alignment; D044967:Serum / Q000276:immunology
chemical_list: D018985:Epitopes, B-Lymphocyte; D015699:HIV Envelope Protein gp120; D007071:Immunoglobulin A, Secretory; D007074:Immunoglobulin G; D011994:Recombinant Proteins; C514793:gp120 protein, Human immunodeficiency virus 1