[Differentiation of type D virus from continuous human cells (Il'in-Bykovskiĭ virus) and Mason-Pfizer monkey virus by the antigens of the viral envelopes].

For differentiation of Ilvin-Bykovsky virus (IBV) and monkey Meson-Pfeizer virus (M-PMV) the method of virus neutralization with antibodies against the envelope virus antigen was used. The viruses were cultivated in similar human embryo cells. The results of the virus neutralization were determined by presence or absence of the gs-antigen in the infected cells. The antiserum to M-PMV envelope antigens did not neutralize the IBV antigen. It has been concluded that IBV and M-PMV differ by their envelope antigens and should be regarded as different viruses.