A 10 minute kinetic neutralization test was used to assess antigenic relatedness among 17 strains of human cytomegalovirus. Hyperimmune guinea pig sera exhibited extensive cross-reactivity. However, the data did suggest that there may be four antigenic groups represented in this collection of CMV strains. Available epidemiologic data for these strains do not provide any discernible basis for this grouping.

Since it appeared that plaque formation in monolayers of primary chick embryo cells might provide a simple technique for the typing of Herpesvirus hominis strains, 100 isolates were tested for their efficiency of plating (EOP) on chick embryo cells versus plating on human embryonic fibroblasts. EOP values varied from 100 to 10-6: 88% of the strains of genital origin had an EOP equal to or greater than 102, and 82% of the oral isolates had an EOP equal to or less than 10-3. Kinetic neutralizations were done with 53 strains, including those 12 with an EOP of 102 or 10-3. An estimate of antigenic relatedness (Ra) between strains was calculated from the neutralization results. Although the site of recovery, EOP, and R. generally correlated, the EOP of some oral strains did not agree with the neutralization results, and some genital strains showed type 1 EOP and R. values. Selection of variants with increased EOP values did not result in accompanying changes in Ra. Thus, the two markers appeared to vary independently. These data support other findings which suggest that there may be no absolute correlation between biological and antigenic markers in herpesviruses and that a larger number with more diversity of strains should be examined for more markers before a typing system is established.on August 5, 2020 by guest http://iai.asm.org/ Downloaded from