Major histocompatibility complex class affinities

The staphylococcal superantigens initially bind to conserved elements on major histocompatibility complex class II molecules with relatively high affinity (A(i 10 mol 1 ). These receptors are found in abundance, throughout the body, on antigen-presenting cells such as macrophages and monocytes. However, each toxin... 

Ironically, SE or TSST-1 concentrations that cause T-cell proliferation do not always correlate with receptor affinity. For instance, SEE binds HLA-DR with 100-fold lower affinity relative to the very similarly structured SEA however, SEE stimulates T-cell proliferation to equivalent levels as SEA. The dose-response curves for cytokine and chemokine production in vitro by staphylococcal superantigen-stimulated cells are also very similar despite differences in affmity/specificity for major histocompatibility complex class II and T-cell receptor V/3 molecules. Overall, these observations suggest that the biological effects of staphylococcal superantigens are induced at rather low, nonsaturating occupancy rates not readily classified by typical biokinetics. 

J. Hammer, C. Bolin, D. Papadopoulos, J. Walsky, J. Higelin, W. Danho, F. Sinigaglia, and Z. A. Nagy, High-affinity binding of shmt peptides to major histocompatibility complex class ii molecules by anchor combinations. Proc. Natl. Acad. Sci. 91, 4456 (1994). 

Recently, oligocarbamates have been used as new ligands for major histocompatibility complex (MHC) class I molecules. A series of pentamers, based on the structure of the natural T-cell epitope SIINFEKL, have been prepared using a flexible automated synthesis [31]. The ligand binding with the highest affinity shows a good structural similarity with the model octapeptide. 

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