‘1-8 interferon inducible gene family': putative colon carcinoma-associated antigens

Db−/−xβ2 microglobulin (β2m) null mice transgenic for a chimeric HLA-A2.1/Db-β2m single chain (HHD mice) are an effective biological tool to evaluate the antitumour cytotoxic T-lymphocyte response of known major histocompatibility-restricted peptide tumour-associated antigens, and to screen for putative unknown novel peptides. We utilised HHD lymphocytes to identify immunodominant epitopes of colon carcinoma overexpressed genes. We screened with HHD-derived lymphocytes over 500 HLA-A2.1-restricted peptides derived from colon carcinoma overexpressed genes. This procedure culminated in the identification of seven immunogenic peptides, three of these were derived from the ‘human 1-8D gene from interferon inducible gene' (1-8D). The 1-8D gene was shown to be overexpressed in fresh tumour samples. The three 1-8D peptides were both antigenic and immunogenic in the HHD mice. The peptides induce cytotoxic T lymphocytes that were able to kill a colon carcinoma cell line HCT/HHD, in vitro and retard its growth in vivo. One of the peptides shared by all the 1-8 gene family primed efficiently normal human cytotoxic T lymphocyte precursors. These results highlight the 1-8D gene and its homologues as putative immunodominant tumour-associated antigens of colon carcinoma

Thymus-derived lymphocytes control the expression of immunogenic properties of peritoneal macrophages.

Macrophages, given keyhole limpet hemocyanin in vitro, from normal mice initiate in culture antigen-specific T cell-mediated immune reactions. On the other hand, macrophages from nude, from adult-thymectomized, or from neonatal-thymectomized mice are impaired with respect to their capacity to signal such an antigen-specific T cell reaction. Thymocytes from hydrocortisone-treated donors, added in culture to such impaired macrophages, rendered them immunologically potent. The capacity of macrophages from adult thymectomized mice to promote the activation of antigen-specific "helper" T cells which, cooperating with B lymphocytes, would lead to antibody production, was also impaired. Thus, it appears that short-lived T lymphocytes control the maturation of macrophages up to a stage at which they can present antigen-specific T cells with antigen in an immunogenic form. We found that such T lymphocytes also control the phagocytic properties of macrophages, yet the impairment of their immunogenic properties does not seem to be derived from decreased phagocytosis

Immunological tolerance: high-dose antigen-induced suppressor cells from tolerant animals inactivate antigen-presenting macrophages.

Studies were carried out to characterize the target cell for the activity of suppressor cells induced in highzone tolerance to deaggregated human gamma globulin (HGG). We applied an in vitro system for the initiation of an immune response, consisting of culturing spleen lymphocytes on HGG-fed macrophages, in which initiator T cells are generated. These cells, when injected into the foot pads of syngeneic mice, recruit specific anti-HGG effector T lymphocytes. We found that HGG-fed macrophages were incapable of signaling spleen cells from HGG-tolerant animals to generate initiator cells. Spleen cells from tolerant animals, when mixed with spleen cells from normal donors, inhibited the capacity of the normal population to give rise to initiator cells after culture on HGG-fed macrophages. Thus, suppressor T cells, which inhibit education of T cells by antigen-fed macrophages, exist in the tolerant spleen. Spleen cells from HGG-tolerant animals, when seeded on macrophages fed simultaneously with HGG and keyhole limpet hemocyanin (KLH), also prevented the macrophages from signaling an anti-KLH response. Spleen cells from HGG-tolerant animals from which the suppressor cells were depleted by “affinity chromatography” on histamine columns, when seeded on macrophages fed with HGG and KLH, generated initiators to both antigens. It appears, therefore, that suppressor cells act at the level of antigen-presenting macrophages, affecting macrophages fed with the tolerogen, and therefore affecting also the immunogenic effect of other antigens presented by the same macrophages. By testing the mode of action of suppressor cells on the tolerogen-fed macrophage, we found that the suppressors manifest a cytotoxic effect on such macrophages. We propose that the suppressor cell is, in fact, an anti modified-self killer, acting on macrophages possessing surface self-antigens “modified” by the tolerogen. The similarity in cell-surface markers between suppressors and anti modified-self killers supports this concept

Author's personal copy A universal epitope-based influenza vaccine and its efficacy against H5N1

a b s t r a c t Previous studies have shown that a recombinant vaccine expressing four highly conserved influenza virus epitopes has a potential for a broad spectrum, cross-reactive vaccine; it induced protection against H1, H2 and H3 influenza strains. Here, we report on the evaluation of an epitope-based vaccine in which six conserved epitopes, common to many influenza virus strains are expressed within a recombinant flagellin that serves as both a carrier and adjuvant. In an HLA-A2.1 transgenic mice model, this vaccine induced both humoral and cellular responses and conferred some protection against lethal challenge with the highly pathogenic H5N1 avian influenza strain. Hence, it is expected to protect against future strains as well. The data presented, demonstrate the feasibility of using an array of peptides for vaccination, which might pave the way to an advantageous universal influenza virus vaccine that does not require frequent updates and/or annual immunizations