N-glycosylation of HIV-gp120 may constrain recognition by T lymphocytes.

The HIV envelope protein gp120 is heavily glycosylated, having 55% of its molecular mass contributed by N-linked carbohydrates. We investigated the role of N-glycosylation in presentation of HIV-gp120 to T cells. T cell clones obtained from humans immunized with a recombinant nonglycosylated form of HIV-gp120 (env 2-3) were studied for their ability to recognize both env 2-3 and glycosylated gp120. We found that 20% of CD4+ T cell clones specific for env 2-3 fail to respond to glycosylated gp120 of the same HIV isolate. Using synthetic peptides, we mapped one of the epitopes recognized by such clones to the sequence 292-300 (NESVAINCT), which contains two asparagines that are glycosylated in the native gp120. These findings suggest that N-linked carbohydrates within an epitope can function as hindering structures that limit Ag recognition by T lymphocytes

N-glycosylation of HIV-gp120 may constrain recognition by T lymphocytes.

Abstract The HIV envelope protein gp120 is heavily glycosylated, having 55% of its molecular mass contributed by N-linked carbohydrates. We investigated the role of N-glycosylation in presentation of HIV-gp120 to T cells. T cell clones obtained from humans immunized with a recombinant nonglycosylated form of HIV-gp120 (env 2-3) were studied for their ability to recognize both env 2-3 and glycosylated gp120. We found that 20% of CD4+ T cell clones specific for env 2-3 fail to respond to glycosylated gp120 of the same HIV isolate. Using synthetic peptides, we mapped one of the epitopes recognized by such clones to the sequence 292-300 (NESVAINCT), which contains two asparagines that are glycosylated in the native gp120. These findings suggest that N-linked carbohydrates within an epitope can function as hindering structures that limit Ag recognition by T lymphocytes.</jats:p

La Rete dei Giardini Fenologici Italiani (Gfi Network)

Gli effetti delle variazioni climatiche sulle specie vegetali possono essere registrati attraverso il monitoraggio delle fasi fenologiche. Queste osservazioni aumentano di significativit\ue0 se protratte nel tempo e confrontate sul territorio. In Italia 11 Giardini e Stazioni di rilevamento fenologico, con cadenza settimanale, rilevano le varie fasi e le mettono in relazione ai fattori climatici. Il loro coinvolgimento all\u2019interno di una Rete, nel rispetto dell\u2019autonomia di ogni giardino, ha come scopo valorizzarne il ruolo, aumentando la visibilit\ue0 e formando una massa critica in grado di interfacciarsi con altre reti internazionali. Ogni Giardino o Stazione, presenta una storia e caratteristiche ambientali proprie; tuttavia, essi hanno in comune alcune specie vegetali. In molti casi, le piante di queste specie sono cloni e questo costituisce un valore aggiunto per la comprensione degli effetti dei fattori ambientali sulla fenologia. In questo contributo si confrontano le caratteristiche delle unit\ue0 della Rete GFI e si presentano i risultati delle prime elaborazioni comuni