Jonathan B. Rothbard

The epitopes of influenza nucleoprotein recognized by cytotoxic T lymphocytes can be defined with short synthetic peptides

A proportion of cytotoxic T lymphocytes (CTL) responding to infection by influenza recognize target cells that express the viral nucleoprotein. Recent work showed that CTL can recognize short overlapping regions of large nucleoprotein fragments expressed in transfected L cells. This led to the suggestion that CTL recognize segmental epitopes of denatured or degraded proteins in a similar way to helper T cells. One corollary of this idea is that CTL should recognize appropriate short peptides on the target cell surface. We demonstrate that the epitopes of nucleoprotein recognized by CTL in association with class I molecules of the major histocompatibility complex in both mouse and man can be defined with short synthetic peptides derived from the nucleoprotein sequence.

Partial T cell signaling: Altered phospho-ζ and lack of zap70 recruitment in APL-induced T cell anergy

Studies of T cell responses to altered peptide ligands (APLs) have provided functional evidence that a T cell receptor (TCR) can interpret subtle changes in its ligand, resulting in different phenotypic outcomes. One dramatic effect of APL stimulation with live antigen-presenting cells (APCs) is the induction of energy as opposed to proliferation. We investigated the intracellular signaling events involved in generating this unresponsiveness by comparing protein-tyrosine phosphorylation patterns after stimulation with anergy-inducing APL or the immunogenic peptide. In resting T cell clones, presentation with APL/live APC stimulated a unique pattern of TCR phospho-zeta species and a subsequent lack of association with zap70. This demonstrates that the TCR-CD3 complex can engage selective intracellular biochemical signaling pathways as a direct consequence of the nature of the ligand recognized and the initial phosphotyrosine pattern of the TCR-CD3 proteins, leading to different phenotypes.

Enhanced recognition of a modified peptide antigen by cytotoxic T cells specific for influenza nucleoprotein

A previously identified Kd restricted epitope of influenza A virus nucleoprotein (147-161) was modified, resulting in recognition by Kd restricted cytotoxic T cells at significantly lower concentrations than the natural peptide sequence. This was achieved by first refining the epitope to the minimum determinant 147-158. Deletion of arginine 156 resulted in a peptide that was shown to be greatly superior in both dose response titrations and in its rate of association with cells to form targets. Analog peptides were tested to determine the important amino acid changes. These data suggest that T cell epitopes can be modified to result in improved immunological recognition.

Structural model of HLA-DR1 restricted T cell antigen recognition

Two human helper T cell determinants in influenza have been identified, one in the hemagglutinin and the other in the matrix protein (M1). Both were shown to be DR1 restricted by using transfected L cells to present antigen. Comparison of the sequences of the two peptides revealed a similar pattern that could account for their DR1 specificity if the peptides adopt a helical conformation. The model was supported by the demonstration that hybrid peptides, composed of the amino acids that interact with DR1 from one determinant and the residues that interact with the T cell receptor from the other, were recognized by each clone. The generality of the motif was confirmed by the finding that DR1 individuals respond to a ragweed peptide containing the defined pattern.

Pattern recognition among T-cell epitopes.

T cells recognize protein antigens by mechanisms qualitatively different from those used by B cells. B cells are capable of binding antigens via their surface immunoglobulins, as in other well-understood ligand-receptor interactions. In contrast, T cells are unable to bind antigen in the absence of the major histocompatibility class I or class II gene products [1]. The details of this possible tertiary interaction are still poorly understood. One puzzling feature of the contrasting recognition processes is that the antigen receptor on T cells exhibits great structural similarity with immunoglobulins [2, 3].

7 – The Epitopes of Influenza Nucleoprotein Recognized by Cytotoxic T Lymphocytes Can Be Defined with Short Synthetic Peptides

A proportion of cytotoxic T lymphocytes (CTL) responding to infection by influenza recognize target cells that express the viral nucleoprotein. Recent work showed that CTL can recognize short overlapping regions of large nucleoprotein fragments expressed in transfected L cells. This led to the suggestion that CTL recognize segmental epitopes of denatured or degraded proteins In a similar way to helper T cells. One corollary of this idea is that CTL should recognize appropriate short peptides on the target cell surface. We demonstrate that the epitopes of nucleoprotein recognized by CTL in association with class I molecules of the major histocompatibility complex in both mouse and man can be defined with short synthetic peptides derived from the nucleoprotein sequence.