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Biomedical subjects

A Sette

Publications and source records attributed to A Sette.

278 records · Page 16Linked to original sources
PubMed1985

Synthetic peptides in the analysis of the induction and regulation of delayed-type hypersensitivity to lysozyme.

T cells mediating hen egg lysozyme (HEL)-specific delayed hypersensitivity can be activated by synthetic peptides of the 1-18 amino acid residues of hen egg lysozyme. The N-terminal 1-18 peptides of hen egg (PHEL) and ring-necked pheasant lysozyme (PREL) are highly cross-reactive in the induction of T cells mediating delayed hypersensitivity. The N-terminal 1-18 peptides of hen egg and ring-necked pheasant lysozyme (PHEL and PREL) are not cross-reactive in the induction of suppressor T cells, demonstrating that phenylalanine at amino acid residue 3 is critical for the formation of an epitope recognized by T suppressor cells.

Amino Acid Sequence↗
PubMedDate not supplied

The development of multi-epitope vaccines: epitope identification, vaccine design and clinical evaluation.

We have developed efficient methods for epitope identification and vaccine design. Our process for epitope selection based on the combined use of motif analyses, binding assays and immunogenicity evaluations is described. We also describe how the projected population coverage and vaccine design can be optimized. Finally, it is discussed how vaccine potency is evaluated by immunogenicity and antigenicity assays.

Epitopes↗
PubMedDate not supplied

HLA expression in cancer: implications for T cell-based immunotherapy.

HLA class I expression is altered in a significant fraction of the tumor types reviewed here, reflecting either immune pressure or, simply, the accumulation of pathological changes and alterations. However, in all tumor types analyzed, a majority of the tumors express HLA class I. with a general tendency for the more severe alterations to be found in later-stage and less differentiated tumors. These results are encouraging for the development of specific immunotherapies, especially considering that (1) the relatively low sensitivity of immunohistochemical techniques might underestimate HLA expression in tumors, (2) class I expression can be induced in tumor cells as a result of local inflammation and lymphokine release, and (3) class I-negative cells would be predicted to be sensitive to Iysis by natural killer cells.

Antigens, Neoplasm↗
PubMedDate not supplied

A basic library of microcomputer programs to obtain immunologically relevant information from protein sequences.

A set of simple and interactive BASIC microcomputer programs which may be used to obtain immunologically relevant information from protein sequences is described. Program listings include the computation of structural dissimilarity between two protein sequences (STRUDIS), the predicted secondary structure (CHOUFAS), their expected degree of three-dimensional similarity by correlation of sequence hydrophobicities (HYDCOR) and the location of alpha-helical segments in the three-dimensional protein structure (HELOC). In addition, a general program is described for running mean calculations (RUNMEAN). All programs are listed in a BASIC version for Apple IIE.

Amino Acid Sequence↗
PubMedDate not supplied

Structural characteristics of an antigen required for its interaction with Ia and recognition by T cells.

A detailed analysis of the residues within an immunogenic peptide that endow it with the capacity to interact with Ia and to be recognized by T cells is presented. Ia interacts with only a few of the peptide residues and overall exhibits a very broad specificity. Some residues appear to interact both with Ia and with T cells, leading to a model in which a peptide antigen is 'sandwiched' between Ia and the T-cell receptor.

Amino Acid Sequence↗
PubMedDate not supplied

Detection of T helper responses, but not of human papillomavirus-specific cytotoxic T lymphocyte responses, after peptide vaccination of patients with cervical carcinoma.

Human papillomavirus type 16 (HPV16)-encoded E7 oncoprotein is constitutively expressed in cervical carcinoma cells and is required for cellular transformation to be maintained. The E7 protein, therefore, forms an attractive target for T-cell-mediated immune intervention to prevent or treat HPV16+ tumors. The authors performed a peptide-based phase I/II vaccination trial to induce anti-tumor immune responses in patients with recurrent or residual cervical carcinoma. Fifteen HLA-A*0201+ patients with HPV16+ cervical carcinoma received vaccinations with synthetic peptides representing 2 HPV16 E7-encoded, HLA-A*0201-restricted cytotoxic T lymphocyte epitopes and a pan-HLA-DR-binding T-helper epitope, PADRE, in adjuvant. No signs of toxicity were observed. Two patients had stable disease for more than 1 year after vaccination, 3 patients died of the disease during or shortly after the vaccination period, and 10 patients maintained progressive cervical carcinoma. Specific immune responses directed against the vaccine components were analyzed in peripheral blood samples. No cytotoxic T lymphocyte responses against the HPV16 E7 peptides were detectable. After vaccination, strong PADRE helper peptide-specific proliferation was detected in 4 of 12 patients. In conclusion, peptide vaccination with 2 HPV16 E7 cytotoxic T lymphocyte epitopes and a universal T helper epitope is well tolerated by patients with advanced cervical carcinoma. Despite a reduction of in vitro cytolytic or proliferative recall responses to some, but not all, conventional antigens in this patient group, peptide-specific proliferative responses were induced in 4 patients. Based on the current study, it is now feasible to perform peptide vaccination in earlier stages of HPV16-induced cervical disease.

Adult↗
PubMedDate not supplied

Antigen analogues as antagonists of the T cell receptor.

Complexes of antigen analogues and major histocompatibility complexes have been demonstrated to function as effective antagonists of the T cell receptor (TCR). It was observed that modification of any of the major T cell contact residues can create powerful TCR antagonists. Increasing similarity of antagonist to antigen structure resulted in increased capacity to act as a TCR antagonist up to a point beyond which the analogues themselves showed antigenicity. These data strongly suggested that peptide: TCR interaction with a certain low affinity may still be sufficient for engagement of the receptor but not for signalling, thus resulting in antagonism. It was found that the presentation of antagonistic peptides alone did not induce the formation of stable conjugates between antigen presenting cells and T cells, but rather that presentation of antigen was required to induce the initial interaction of APC with T cells in cell:cell conjugates. This antigen-dependent conjugate formation was not affected by the antagonist, while very early intracellular biochemical events such as PI turnover and CA2+ flux were inhibited.

Antigen-Presenting Cells↗