Abstract

Ever since the emergence of models for the processing and presentation of antigenic determinants by MHC class II molecules, the main view has been that proteins are unfolded, enzymatically cleaved into peptide lengths of about 12–25 amino acids and then loaded onto MHC class II molecules. There is, however, an alternative model stating that partially intact unfolding antigens are first bound by MHC class II molecules and then trimmed to fragments of a smaller size while remaining bound to the MHC class II molecule. In this analysis, we make the case that a considerable portion of the elutable peptide cargo belongs to this latter class.

Author affiliations

1. Torrey Pines Institute for Molecular Studies, San Diego, California 92121, USA.
2. Harvard Medical School, Boston, Massachusetts 02115, USA.

Correspondence to: Eli E. Sercarz¹ Email: esercarz@tpims.org