Reproduction of vaccinia virus (strain neurolapina) in rabbit blood leucocytes in vitro.

The determining factor in vaccinia virus reproduction is the initial pattern and subsequent development of the given cell populations, in relation to the infection multiplicity, interferon production and other factors. The sensitive cells in fresh suspensions may be the blood monocytes and the small lymphocytes are virus-resistant. In cultures, transformed lymphocytes (blast cells) and macrophages play the major role in virus reproduction. The macrophages are probably of greater significance for the production of infectious virus. Replication of virus antigen was initiated in the polymorphonuclear cells in exceptional cases only, and only in the presence of a larger infection dose.