LYMPHOPROLIFERATIVE RESPONSES AFTER INFECTION WITH HUMAN PARVOVIRUS B19

Immunity after infection with the parvovirus B19 is assumed to be conf erred by a humoral immune response with development of neutralizing an tibody. In contrast, little is known about the nature of T-cell-mediat ed responses to parvovirus B19 infection in humans. We used recombinan t proteins VP1, VP2, and NS1, as well as a recombinant VP1-specific am ino-terminal sequence, to test the proliferative responses of peripher al blood mononuclear cells after infection of otherwise healthy indivi duals with parvovirus B19, These proteins were used as antigens for th e stimulation of freshly isolated cells. The results show that a B19 v irus-specific cellular immunity develops that is directed against the capsid proteins VP1 and VP2. We also demonstrate that viral determinan ts are presented to CD4(+) T cells by HLA class II molecules.