Influenza viruses and cross-reactivity in healthy adults: humoral and cellular immunity induced by seasonal 2007/2008 influenza vaccination against vaccine antigens and 2009 A(H1N1) pandemic influenza virus.

We analyzed humoral and cellular immune responses against vaccine antigens and the new A(H1N1) virus in healthy adults before and after immunization with the 2007/2008 commercially available trivalent subunit MF59-adjuvanted influenza vaccine during the Fall 2007, prior to the emergence of the new virus. Antibody titers were significantly boosted only against the three vaccine antigens. Seasonal vaccination boosted pre-existing cellular responses upon stimulation of peripheral blood mononuclear cells not only with the homologous three vaccine antigens, but also with the heterologous new 2009 A(H1N1) and with a highly conserved peptide present in the stalk region of hemagglutinin (HA).

CD1-restricted recognition of exogenous and self-lipid antigens by duodenal gammadelta+ T lymphocytes.

Gammadelta T cells are present in the mucosal intestinal epithelia and secrete factors necessary to maintain tissue integrity. Ags recognized by these cells are poorly defined, although in mice non-classical MHC class I molecules have been implicated. Since MHC class I-like CD1 receptors are widely expressed at the surface of epithelial and dendritic intestinal cells and have the capacity to present lipid Ags to T cells, we hypothesized that these molecules might present autologous and/or exogenous phospholipids to intestinal gammadelta T lymphocytes.

Recognition of pollen-derived phosphatidyl-ethanolamine by human CD1d-restricted gamma delta T cells.

Background: Evidences from mice and human beings indicate that gammadelta T cells could be relevant in recognition of stress-induced self and/or yet unidentified inhaled foreign antigens. Their specificity differs from classic MHC-restricted alphabeta T cells and involves the immunoglobulin-like structure of the gammadelta T-cell receptor with the recognition of small organic molecules, alkylamines, and self lipid compounds presented by CD1+ dendritic cells.

Objective: Because CD1 receptors are mainly devoted to lipid antigen presentation, we sought to determine whether exogenous pollen membrane lipids may act as allergens for CD1-restricted gammadelta T cells.

Biochemical and immunological characterization of pollen-derived beta-galactosidase reveals a new cross-reactive class of allergens among Mediterranean trees.

Background: The most potent allergens in the Spermatophytae family exhibit significant homology with enzymes. Some of these are though to be involved in pectin metabolism, recognition of compatible stigma and delivery of sperm cells to the ovule.

Objective: To test if glycohydrolase activities from some Mediterranean tree pollens could act as allergens in sensitized hosts.