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Enhancing cytotoxic t cell responses with altered-peptide ligands

100%

Zhao R., Collins E. J.

Archivum Immunologiae et Therapiae Experimentalis

2001

vol. 49

issue 4

271-278

Interest in class I MHC-mediated immunotherapy is growing rapidly. In order to fight a virus or cancer effectively, a successful immunotherapeutic must activate a large number of specific CD8+ T cells and also generate immunological memory. Attempts to generate immune responses towards tumor- or virus-derived peptides have frequently been frustrated by the nature of the peptide antigen itself. Either the peptide does not bind well to its cognate MHC, or the T cells directed towards it have been functionally inactivated in vivo. Altered-peptide ligands are an effective way to circumvent these problems. However, generating enhanced binding of altered peptides to class I MHC while still maintaining recognition of the wild-type peptide is not straightforward. Many groups design enhanced binding peptides by substituting the observed anchor residues with those that are most preferred by the class I MHC molecule. For many antigenic peptides, this approach does not work. Furthermore, if a higher affinity peptide is designed, the substitutions may result in reduced recognition by CD8+ T cells. Therefore, the design of an altered-peptide ligand requires careful testing of each candidate therapeutic in terms of affinity for class I MHC and immunological reactivity. Lastly, immunotherapy using class I MHC must also take into account the large genetic heterogeneity in the population. A therapeutic that is only effective for 5-10 percent of the population is not as attractive as one that works for over 90% of the population. The use of MHC supertypes (groups of class I MHC allotypes that share similar peptide-binding characteristics) shows great promise in overcoming this problem.

Beta 3-Integrin cytoplasmic binding proteins

81%

Zhao R., Pathak A. S., Stouffer G. A.

Archivum Immunologiae et Therapiae Experimentalis

2004

vol. 52

issue 5

348-355

Integrins are cell-surface adhesion receptors that play an important role in mediating numerous physiological processes, including inflammation, migration, adhesion, and proliferation. Integrin regulation by events within the cell has been termed 'inside-out' signaling; this is a capacity that is unique to integrin receptors. As is typical of other cell-surface receptors, integrins can also transduce signals from outside the cell into the cytoplasm on binding extracellular ligands ('outside-in signaling'). Integrins are composed of an alpha and a beta subunit, which form a heterodimer. The beta 3-integrin family consists of alphaIIbbeta3 found on platelets and megakaryocytes, and the more widely distributed alpha beta3. beta subunits consist of a large extracellular domain, a single transmembrane segment, and a relatively short cytoplasmic tail. The cytoplasmic domains do not contain intrinsic tyrosine kinase activity, and therefore signaling occurs primarily via recruitment of intracellular signaling molecules. Integrins form transmembrane connections, and the interactions between integrin cytoplasmic domains, intracellular factors (cytoplasmic proteins and intracellular signaling pathways), and membrane-anchored proteins play an important role in integrin- mediated events. There are at least 21 proteins that associate with integrin beta tails to regulate cell motility, proliferation, differentiation, and apoptosis. In this review, we will focus on 10 of these proteins and their function in integrin-mediated events.

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2 Archivum Immunologiae et Therapiae Experimentalis

1 2004

1 2001

2 Zhao R.

1 Collins E. J.

1 Pathak A. S.

1 Stouffer G. A.

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Enhancing cytotoxic t cell responses with altered-peptide ligands

Beta 3-Integrin cytoplasmic binding proteins