Welcome to the Landry Lab
Samuel J Landry, Ph.D.
Professor of Biochemistry
Our work employs biochemical and biophysical techniques to investigate structure/function relationships in protein-protein interactions, especially those involved in cellular stress and immune responses.
Structural Instability and T-cell Epitope Immunodominance. Humoral and cellular immunity to HIV and other pathogens depend on antigen-specific CD4+ T cell responses directed against peptides presented in MHC class II antigen presenting proteins. Generally, CD4+ T-cell responses are focused on only a few immunodominant regions of naturally processed antigens. We have found that immunodominant regions occur in the sequences flanking locally unstable segments of an antigen's three-dimensional structure. We are now modifying CD4+ helper T-cell immune responses to recombinant antigens by engineering their processing and presentation, and studying how the specificity of the CD4+ T-cell response influences the effector phases of the immune response.
Relevance to Medicine
Epitope mapIn our work on T-cell epitope immunodominance, we investigate how the immune system zooms in on key features of foreign and self proteins, as it fights off invaders but avoids causing autoimmune disease. The immune system recognizes bacteria, viruses, and toxins through surveillance by antibodies and T-cell receptors. Antibodies act alone to recognize intact foreign antigen molecules; whereas, T-cell receptors recognize pieces (epitopes) of antigen molecules that have been broken down and presented on the surface of specialized antigen-presenting cells. This dual-aspect recognition nearly ensures that the immune system will not attack our own molecules. Our work has shown that the process of antigen breakdown tends to focus the immune system on certain pieces of proteins. We suspect that bacteria and viruses have evolved to misdirect the immune system toward highly variable or otherwise less effective protein segments. We are attempting to overcome this misdirection by engineering subunit vaccines so that the immune system focuses on the most important antigen segments. Understanding how the immune systems distinguishes self from non-self will allow us to develop strategies to treat and prevent asthma and other forms of allergy.
Current Research Grants
Tulane University, New Orleans, LA 70118 504-865-5000 firstname.lastname@example.org