Relation of Pock Size on Chorioallantoic Membrane to Antigenic Type of Herpesvirus Hominis

Abstract

Recently we have observed that strains of herpesvirus hominis (HVH) could be differentiated antigenically into two types. Type 1 was found to be primarily associated with nongenital infection and transmission, whereas type 2 was primarily associated with genital infection and transmission (1). In order to further characterize the two antigenic types, biologioal markers were sought. Other investigators (2)(3)(4) found that the pock size on embryonated egg choridlantoic membrane (CAM) with certain HVH strains were larger. In addition, various types of histological changes have ;been observed (5-8) in the CAM after infection with different HVH strains. This report presents studies on the relation of pock size on CAM to antigenic type Olf 79 strains of HVH which were isolated from genital and nongenital sites, and suggests the use of this technique as a presumptive test far the differentiation of HVH strains. Histological studies of the CAM infected with serotypes 1 and 2 also are included.Materials and Methods. Virus strains. The source and passage history of the majority of the strains used for this study have been described ( 1 ) . In addition, 4 strains isolated from eye infections, 2 from infections of newborns and a vaginal isolate from an 8-year-old *Supported in part by AI-06157 from National Institutes of Health, USPHS. A. Nahmias is recipient of a Research Career Development Award, IK-AT-18637 from the USPHS.girl are included. The majority of strains were primary isolates with 1 or 2 tissue culture passages, mainly in primary ,rabbit kidney cells. Only 2 strains had prior egg passage.Egg inoculation. Embryonctted eggs 10-1 2 days old were inoculated with 0.1 ml of varying dilutions of virus on the CAM using the false air sac technique (9). At least 2 eggs were inoculated with each virus dilution and the eggs were incubated at 34-35OC for 3-4 days. T o avoid the possible effect of population density on pock size, measurements were made, whenever f easilble, when the number of pocks was between 20 and 100. The membrane was removed onto a plate containing saline. The morphology of the pocks was examined and the &meter of the pocks was measured with the aid of an ocular micrometer mounted to the eyepiece of a binocular dissection microscope. Strains-which did not produce pocks with undiluted virus were tested at least twice.Criteria far "large" and "small" pocks. Up to 2 0 pocks were measured for each strain. Virus strains were divided into those producing "small" or "large" pocks on the h i s of the following criteria: Small-average diameter of pocks counted was less than 0.5 mm and diameter of any one pock did not exceed 1.0 mm (Fig. 1). Large-Average diameter of pocks counted was greater than 0.5 mm and many pocks exceeded 1 mm in diameter (Fig. 2 ) . Pock size measuiremenlts were made on

Efficiency of the use of pock size on the chorioallantoic membrane of fertile hen's eggs as a method of typing herpes simplex viruses

“…The size of the pocks produced on the membrane was estimated and used to differentiate between type 1 and type 2 strains of HSV. The production of large pocks has been associated with type 2 strains of HSV and smaller pocks with type 1 strains (Nahmias et al 1968). Viruses producing pocks with an average diameter of greater than 0 5 mm were typed as HSV-2, whereas viruses giving smaller pocks were classed as HSV-1.…”

Plaque Assay of Herpesvirus Hominis on Human Embryonic Fibroblasts

“…Comparable assays were obtained with four strains of fibroblasts and all herpesvirus strains tested plaqued equally well on fibroblasts. Although pock size on the + chorioallantoic membrane has "tgen used to differentiate Type 1 from Type 2 herpesvirus strains (8), plaque size on fibrobasts did not vary with type or strain. Plaques produced by the Type 1 strains UW-165, UW-168, E-2 7 7, and E-115 could not be distinguished from plaques produced by Type 2 UW-268, E-304, and E-326.…”

Identification of strains of herpes simplex virus by comparison of the density of their DNA using the preparative ultracentrifuge

“…Various serological tests such as microneutralization [PAm~S and DOWDLE (25)] kinetic neutralization [DESS~¥TER et al (3)], neutralization with antisera absorbed with heterologons antigen [SIM and WATSO~ (34)], plaque reduction [ScHsEWEIS (33); PLUMMER (27)], complement fixation [NAgMIAS et al (20)], direct immunofluorescent technique [NA~I}a~AS et al (22)] and microindireet haemagglutination test [Fucc~Lo et al (6)] have been used to determine the antigenic type of isolates. In addition, the two types differ in various biological properties such as the size of pocks formed on the chorioMlantoic membrane of chick embryos [SCItNEWEIS (33); PARKER and :BANATVALA (24~); NAHML~S et al (21)] and tissue culture cytopathic effect [MIY~K and DO~ER (19); EJERCITO, KIEFIr and ROIZMAN (5); PLUMMER, WANER and BOWLIN¢ (28)]. …”