Abstract
We have previously described the development of virus-specific helper T cell hybridomas which recognize structural determinants shared by type 1 and type 3 reoviruses that have been exposed to UV radiation. We have found that T-cell hybridomas become persistently infected with live type 3 reovirus used for the immunization. Persistently infected T-hybridoma cells were found to spontaneously produce interleukin 2 (IL-2). To analyze the mechanism of induction of IL-2 secretion of persistently infected T-cell hybridomas, we exposed T-cell hybridomas specific for UV-treated virus to replicating type 3 reovirus. The T-cell hybridomas became infected but did not produce IL-2 unless simultaneously exposed to syngeneic I-A+ antigen-presenting cells. In this situation, the persistently infected T-cell hybridomas produced IL-2 without being reexposed to virus. This process was not a consequence of nonspecific IL-2 gene activation, which occurs in cells persistently infected with reovirus, because reovirus infection did not activate IL-2 secretion in T-cell hybridomas with other antigenic specificities. Reovirus exposure also resulted in persistent infection of certain antigen-presenting B-cell tumor lines. The persistently infected B-cell tumor lines could stimulate reovirus-specific helper T cells but not T-cell hybridomas of other specificities. The data support the thesis that persistent infection of reovirus-specific T cells creates a mechanism in which the virus released from these cells is processed and then reexpressed by I-A+ antigen-presenting cells. The IA antigen and reovirus structures on the antigen-presenting cells then restimulate the T cells through their specific receptors, resulting in IL-2 synthesis and release. These observations may be relevant to mechanisms of autoimmunity induced by virus.