Normal B-cell Activation Involves Endogenous Retroviral Antigen Expression: Implications for Leukemogenesis

Abstract

brate species contain information for C-type retro-viruses, i.e., endogenous viruses. The origin of these viruses is unclear. They could represent originally exogenous viruses that have integrated into the germ line DNA of some species. In fact, there is evidence that under natural (Benveniste and Todaro 1974) and laboratory (Jaenisch 1976) conditions retroviruses can become part of a species ' germ line. In an attempt o explain the origin of proviral DNA, Temin (1971) has proposed that viral DNA is derived from protoviral host genes that carry out physiological functions. Once a provirus has been generated, it can spread and ultimately enter the germ line of the original species and other species. Thus, it is possible that normal DNA contains both protoviral functional genes and