Peptides that Stabilize Protein Antigens and Enhance Presentation to CD8+ T Cells
Description of Invention:
This invention relates to compositions and methods for stabilizing an antigen against proteolytic degradation and enhancing its presentation to CD8+ cells. The invention claims "fusion agents," isolated molecules comprising a hydrophobic peptide joined to an epitope to which a CD8+ T cell response is desired. Also claimed in the invention are the nucleic acid sequences that encode the fusion agents. Recently, there has been great interest in developing vaccines to induce protective CD8+ T cell responses, however, there are practical obstacles to this goal. Although purified antigenic peptides are effectively presented in vitro, introduced in a purified form they often do not stimulate effective T cell responses in vivo because the antigens are insufficiently immunogenic and too easily degraded. Adjuvants or infectious "carriers" often can enhance these immune responses, however, these added agents can cause unacceptable local or systemic side effects. The present invention increases antigen stability and promotes in vivo responses in the absence of an adjuvant or active infection.
The invention describes three variants of lemA, an antigen recognized by CD8+ cells in mice infected with Listeria monocytogenes. The antigenic and stabilizing properties of lemA can be accounted for by the covalent association of the immunogenic aminoterminal hexapeptide with the protease resistant scaffolding provided by amino acids 7 to 33 of the lemA sequence (lemA(7-33)). Variants t-lemA, and s-lemA bearing an antigenic sequence immediately preceding lemA(7-33), and lemS containing an immunogenic sequence immediately after lemA(7-33), each induce a CD8+ T cell response and protect the crucial immunogenic oligopeptide from protease degradation. The site of antigen insertion relative to lemA(7-33) can influence antigen processing by preferentially promoting processing either in the cytoplasm or endosomal compartment. Therefore, several embodiments of the invention involve the construction of antigen processing protein molecules and their methods of use. Alternatively, a DNA sequence coding lemA(7-33) may be inserted at an appropriate site to enhance the immunogenicity of the antigenic element coded by a DNA vaccine. In sum, this invention is an attractive, nontoxic alternative to protein/adjuvant combinations in eliciting CD8 responses in vivo and a useful element for enhancing the efficiency with which products coded by DNA vaccines are processed and presented in vivo. Because lemA(7-33) is particularly effective in protecting oligopeptides from proteases, this invention may have particular usefulness in enhancing local T cell at sites such as mucosal surfaces where there may be high proteolytic activity.
A related article was published in the Journal of Immunology at: 1999;163:6741-6747.
Inventors:
Roger Kurlander (CC) Elizabeth Chao (CC) Janet Fields (CC)
Patent Status:
DHHS Reference No. E-172-1999/0 --
U.S. Provisional Application No. 60/169,227 filed 06 Dec 1999
PCT Application No. PCT/US00/33027 filed 12 Dec 2000, which published as WO 01/40275 on 07 Jun 2001
For Additional Information Please Contact: Peter A. Soukas J.D.
NIH Office of Technology Transfer
6011 Executive Blvd, Suite 325
Rockville, MD 20852-3804
Phone: (301) 435-4646
Email: soukasp@mail.nih.gov
Fax: (301) 402-0220
