CONTENTS

Introduction..................................................................................................................................... 56

Overview..................................................................................................................................

T Cell Development in the Thymus......................................................................................... 56

HIV Infection of Thymocyte Subsets.............................................................................................. 57

The Thymus as a Reservoir of HIV.......................................................................................... 57

Infection of Thymocytes.......................................................................................................... 57

Infection of Thymic Stromal Cells.......................................................................................... 58

Thymic Architecture....................................................................................................................... 59

Thymic Histology..................................................................................................................... 59

Thymic Pathology during HIV Infection................................................................................. 59

The Aging Thymus................................................................................................................... 59

Early T Cell Ontogeny and Hematopoiesis..................................................................................... 59

Thymopoiesis........................................................................................................................... 59

Hematopoiesis..........................................................................................................................

Thymic Selection and T Cell Maturation....................................................................................... 60

Positive and Negative Selection.............................................................................................. 60

Tolerance to HIV...................................................................................................................... 60

Thymocyte Signaling and Death Mechanisms........................................................................ 61

Thymic Microenvironment............................................................................................................. 63

Thymocyte-Stroma Cross Talk................................................................................................ 63

Disruption of the Thymic Microenvironment......................................................................... 63

Indirect Effects of HIV on the Thymus.................................................................................... 65

Thymic Output and T Cell Homeostasis......................................................................................... 65

Attrition of T Cells................................................................................................................... 65

Thymic Output......................................................................................................................... 66

Peripheral Expansion............................................................................................................... 67

Effects of Anti-HIV Therapy on the Thymus................................................................................. 67

HAART..................................................................................................................................... 67

Cytokines.................................................................................................................................. 68

Summary.......................................................................................................................................... 68

References....................................................................................................................................... 68