Document Type


Date of Degree

Fall 2011

Degree Name

PhD (Doctor of Philosophy)

Degree In


First Advisor

Morita, Craig T.

First Committee Member

Harty, John T.

Second Committee Member

Hohl, Raymond J.

Third Committee Member

Perlman, Stanley

Fourth Committee Member

Varga, Steven M.


Human γδ T cells expressing the Vγ2Vδ2 T cell antigen receptor play important roles in immune responses to microbial pathogens by monitoring prenyl pyrophosphate isoprenoid metabolites. Most adult Vγ2Vδ2 cells are memory cytotoxic cells that produce interferon-γ (IFN-γ). Recently, murine γδ T cells were found to be major sources of interleukin (IL)-17A in anti-microbial and autoimmune responses. To determine if primate γδ T cells play similar roles, we characterized IL-17A and IL-22 production by Vγ2Vδ2 T cells. IL-17A-producing memory Vγ2Vδ2 T cells exist at low but significant frequencies in adult humans (1:2,762 T cells) and at even higher frequencies in adult rhesus macaques. Higher levels of Vγ2Vδ2 T cells produce IL-22 (1:1,864 T cells) although few produce both IL-17A and IL-22. Unlike adult humans where many IL-17A+ V#947;2Vδ2 T cells also produce IFN-#947; (T#947;δ1/17), the majority of adult macaques IL-17A+ Vδ2 T cells (T#947;δ17) do not produce IFN-#947;. To define the cytokine requirements for T#947;δ17 cells, we stimulated human neonatal V#947;2Vδ2 T cells with the bacterial antigen, (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate, and various cytokines and mAbs in vitro. We find that IL-6, IL-1β, and transforming growth factor-β (TGF-β) are required to generate T#947;δ17 cells in neonates whereas T#947;δ1/17 cells additionally required IL-23. In adults, memory T#947;δ1/17 and T#947;δ17 cells required IL-23, IL-1β, and TGF-β but not IL-6. IL-22-producing cells showed similar requirements. Both neonatal and adult IL-17A+ V#947;2Vδ2 T cells expressed elevated levels of retinoid-related orphan receptor-#947;t. Our data suggest that, like Th17 αβ T cells, V#947;2Vδ2 T cells can be polarized into T#947;δ17 and T#947;δ1/17 populations with distinct cytokine requirements for their initial polarization and later maintenance.


Cell Differentiation, Humans, Interleukin-17A, Interleukin-22, Receptors, Antigen, T-Cell, gamma-delta, T-Lymphocyte Subsets


x, 119 pages


Includes bibliographical references (pages 92-119).


Copyright 2011 Kristin Jennifer Ness-Schwickerath