The immune response to human cytomegalovirus-induced early nuclear and early membrane antigens and its possible clinical significance.

Before replication of the human cytomegalovirus (HCMV) genome takes place, two major antigenic complexes are induced in the infected cell by an early expression of parental viral genome: one (Early antigen or EA) is localised in the nucleus, the other (Early membrane antigen or EMA) on the plasma-membrane. Sequential samples of serum from renal transplant recipients, pregnant women, blood donors and patients with known HCMV disease were examined by means of indirect immunofluorescence tests for the presence of IgG, IgM and IgA antibodies against EA and EMA. Serum antibody reacting with EMA belongs almost exclusively to the IgM class while that reacting with EA may be of the IgG, IgM or IgA class. IgM antibody to EMA seems to be preferentially associated with primary active HCMV infection.