Department of Internal Medicine

Immunology Faculty


Craig Morita photo

Medical School:
University of California,
San Francisco

Residency:
University of California,
San Diego
Boston University

Fellowship:
Harvard Medical School
Brigham and Women's Hospital

Craig T. Morita, M.D., Ph.D.
Associate Professor
Coordinator, Rheumatology Fellowship Program

My lab focuses on the study of human γδ T cells and nonpeptide antigens. γδ T cells are a distinct subset of T cells that function to bridge innate and adaptive immunity by recognizing nonpeptide, isoprenoid metabolites and by performing unique roles not played by αβ T cells. Pathogen recognition by human γδ T cells is very important in microbial immunity as evidenced by the large expansions of Vγ2Vδ2 T cells (up to 1 in 2 circulating T cells) that occur during many bacterial and parasitic infections. Moreover, once activated, Vγ2Vδ2 T cells kill most types of tumors by recognizing them using the NK receptors that they express. Thus, efforts are ongoing to determine how to use Vγ2Vδ2 T cells for cancer immunotherapy.

We have found that human γδ T cells use their Vγ2Vδ2 antigen receptors to recognize essential phosphorylated metabolites in isoprenoid biosynthesis. Bacteria and protozoan parasites use a distinct metabolic pathway to make isoprenoids. Vγ2Vδ2 T cells recognize one of the intermediates in this pathway, termed HMBPP. They also recognize the self-metabolite, IPP, which accumulates in cells after aminobisphosphonate drug treatment. One area of focus of the lab is to determine how these small phosphoantigens are presented to Vγ2Vδ2 T cells by identifying its novel antigen presenting molecule. We are also working to identify a novel bacterial antigen produced by Staphylococcus aureus and to determine the role of Vγ2Vδ2 T cells in immunity to Gram-positive cocci.

A second area of study has focused on the development of memory in γδ T cells. We find that distinct memory subsets of Vγ2Vδ2 T cells exist. These Vγ2Vδ2 subsets have different migratory and functional abilities. The different migration is due to differential expression of adhesion molecules and chemokine receptors that determine the homing capabilities of cells. Our present studies focus on the factors that control the generation of memory Vγ2Vδ2 T cells and the relative importance of the different memory subsets in bacterial and tumor immunity.

A third area of study is to develop γδ vaccines for bacterial infections and for cancer immunotherapy. In clinical trials, stimulating Vγ2Vδ2 T cells has resulted in partial and complete remissions in some cancer patients with lymphoma, prostate cancer, and renal cell carcinoma. We are testing new lipophilic bisphosphonates as vaccines for γδ T cells. We are also engineering the metabolism of vaccine bacteria to make them overproduce the HMBPP antigen. In preclinical studies, we are testing these different vaccines in monkeys and in immunodeficient mice transplanted with human blood cells.

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Honors, Awards, and Organizations

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