Our general goal is to understand the relationship of Ii to the expression, cycling, and function of Ia on normal and transformed cells. Several model systems of leukemic, virus-transformed or activated normal lymphoid cells demonstrate Ii hyperexpression and can be used to define mechanisms regulating Ii synthesis, processing, and influence on Ia function. These models include cells of a unique subset of patients with hairy cell leukemia, P3HR-1 Epstein-Barr virus (EBV) superinfected Raji cells, butyrate-treated P3HR-1 lymphoblastoid cells, and polyclonally-activated B and T lymphocytes. Variations in structure and rates of processing of Ii and Ia in these systems will be quantitated, including definition of post-translational modifications and kinetic analysis of mRNA structure and amounts in these cells as a function of transformation or activation. Structural epitopes on Ii will be defined with monoclonal antibodies and related to external and internal domains to sites of interaction with Ia and to expression of function. Hypotheses to test the function of Ii will include: (1) the view that Ii is a transporter of Ia to membranal-coated pits where it remains as a potential receptosome anchor protein (an entity postulated by Pastan et al.); (2) that Ii directs, further, the cycling of Ia which has been expressed on the cell surface into receptosomes within the cell; (3) that a small but identifiable subpopulation of li molecules operates as a transducer of Ia function; and (4) that Ii interacts with membrane molecules in addition to Ia and could be an oncogene product or induced by oncogene function. While this project should well define structure of Ii in terms of chemistry, kinetics, and immunogenic domains, we expect to relate these basic findings to the function of Ii. In particular, we seek to explain why Ii is so prominently expressed on some B-lineage human leukemias, on EBV-superinfected cells (as a principal, host cell gene-coded, EBV-induced protein), and (apparently, transiently) on activated normal lymphocytes. Understanding such processes leads to a better understanding of the immunobiology of these cell populations and could contribute to developing options to therapeutically alter that biology. (AG)

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA037645-05
Application #
3175431
Study Section
Immunobiology Study Section (IMB)
Project Start
1984-07-01
Project End
1990-05-31
Budget Start
1988-06-01
Budget End
1990-05-31
Support Year
5
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of Massachusetts Medical School Worcester
Department
Type
Schools of Medicine
DUNS #
660735098
City
Worcester
State
MA
Country
United States
Zip Code
01655
Nguyen, Q V; Knapp, W; Humphreys, R E (1993) Characterization of the invariant chain C-terminus (Glu183-Glu193) epitope which is obscured in processed Ii, MHC alpha,beta trimers. Mol Immunol 30:1679-84
Nguyen, Q V; Roskey, A M; Humphreys, R E (1993) Effects of brefeldin A on cleavage of invariant chain to p21 and p10 and the appearance of Ii-freed class II MHC dimers. Mol Immunol 30:137-44
Lu, S; Reyes, V E; Bositis, C M et al. (1992) Biophysical mechanism of the scavenger site near T cell-presented epitopes. Vaccine 10:3-7
Lam, V; Thomas, L J; Kostyal, D A et al. (1992) Highly conserved, potential cleavage sites about the desetopes of MHC class I and class II molecules. Tissue Antigens 39:26-31
Reyes, V E; Lu, S; Humphreys, R E (1991) Binding of radioiodinated influenza virus peptides to class I MHC molecules and to other cellular proteins as analyzed by gel filtration and photoaffinity labeling. Mol Immunol 28:341-8
Reyes, V E; Lew, R A; Lu, S et al. (1991) Prediction of alpha helices and T cell-presented sequences in proteins with algorithms based on strip-of-helix hydrophobicity index. Methods Enzymol 202:225-38
Lu, S; Ciardelli, T; Reyes, V E et al. (1991) Number and placement of hydrophobic residues in a longitudinal strip governs helix formation of peptides in the presence of lipid vesicles. J Biol Chem 266:10054-7
Sairenji, T; Daibata, M; Sorli, C H et al. (1991) Relating homology between the Epstein-Barr virus BOLF1 molecule and HLA-DQw8 beta chain to recent onset type 1 (insulin-dependent) diabetes mellitus. Diabetologia 34:33-9
Reyes, V E; Fowlie, E J; Lu, S et al. (1990) Comparison of three related methods to select T cell-presented sequences of protein antigens. Mol Immunol 27:1021-7
Sorli, C H; Reisert, P S; Welch, W J et al. (1990) Identification of p70 and p80 associations with class II MHC molecules and Ii. Am J Hematol 35:157-66

Showing the most recent 10 out of 27 publications