Replication of canine herpesvirus. II. Virus development and release in infected dog kidney cells

Properties and functions of feline herpesvirus type 1 glycoproteins

Feline herpesvirus type 1 (FHV-1) is a causative agent of feline viral rhinotracheitis and belongs to the subfamily Alphaherpesvirinae of the family Herpesviridae. Since first isolated in 1958 by Crandell and Maurer, FHV-1 is distributed worldwide and is the most clinically significant agent for respiratory infections in cats. In this review, we describe the recent findings with properties and functions of FHV-1 glycoproteins, especially hemagglutinins.

Characterization of canine herpesvirus glycoprotein D (hemagglutinin)

Glycoprotein D (gD) of canine herpesvirus (CHV) YP2 strain was expressed in COS-7 and insect (Spodoptera frugiperda; Sf9) cells. The gDs expressed in COS-7 and Sf9 cells reacted with a panel of monoclonal antibodies (MAbs) against CHV gD (hemagglutinin) and an MAb 25C9 against feline herpesvirus type 1 (FHV-1) gD by indirect immunofluorescence assay, and possessed a molecular weight (MW) of approximately 51-55 and 41-46 kilodalton (kDa), respectively, when examined by immunoblot analysis. After treatment with tunicamycin, the MW of the gD expressed in Sf9 cells became approximately 37 kDa. By hemadsorption (HAD) tests using canine or feline red blood cells (RBC), COS-7 cells expressing CHV gD adsorbed only canine RBC, but not feline RBC, whereas control COS-7 cells expressing FHV-1 gD adsorbed feline RBC, but not canine RBC. By hemagglutination (HA) tests, lysates of Sf9 cells expressing CHV gD agglutinated canine RBC, but not feline RBC. These HA and HAD activities were inhibited by HA-inhibition MAbs against CHV gD. Control lysates of Sf9 cells expressing FHV-1 gD agglutinated only feline RBC. Serum from mice inoculated with lysates of Sf9 cells expressing CHV gD possessed a high titer of virus-neutralizing activities against CHV infection. These results indicated that CHV gD is structurally similar to FHV-1 gD, but is functionally different from FHV-1 gD.

Human cytomegalovirus morphogenesis: an ultrastructural study of the late cytoplasmic phases

The late cytoplasmic phases of human Cytomegalovirus (HCMV) morphogenesis in cultured fibroblasts have been studied by transmission electron microscopy focusing attention on the relationship between the viral particles and host cell organelles. The results obtained largely reflect changes in cells subjected to sublethal injurious stimuli induced by many viruses as well as different noxious agents. A great increase in the number of Golgi apparatuses and lysosomes was observed, both of them interacting with the viral progeny. HCMV seems to acquire its final envelope from Golgi-derived structures and, less frequently, from the plasma membrane.

Morphological observations of the replication of herpesvirus tamarinus in RL-33 cells

The replication in RL-33 cells (rabbit lung cell line) of herpesvirus tamarinus isolated from cotton-topped marmosets (Saguinus oedipus) was investigated by electron microscopy. In the early stages of infection, ring-shaped and granular structures, and fibrillar materials were recognized in the nucleus. Immature particles were often found in such nuclei. The envelope of the virus was formed by budding through intracytoplasmic membranes, the inner nuclear membrane or the membrane of intracytoplasmic vacuoles. Virus particles which appeared to be budding through the plasma membrane were also observed. Aberrant viral forms were produced by independent budding of both the inner and outer nuclear membranes. The mature particles once enveloped acquired a second envelope by budding through intracytoplasmic double membranes or the outer nuclear membrane. Unusual virus-associated structures were observed in the cytoplasm and nucleus. Virus particles appeared to be released by the process of reverse phagocytosis.

Studies on Herpesvirus scophthalmi infection of turbot Scophthalmus maximus (L.) ultrastructural observations

Abstract. Recent heavy mortalities amongst O+ group turbot at a fish farm were found to be associated with a herpes‐type viral infection of the epithelia of the skin and gills. The morphology of the virus is described with ultrastructural observations on its morphogenesis and release from infected cells.

Immunodiagnostic potential of a virus-coded, tumor-associated antigen (AG-4) in cervical cancer

The central theme of this communication is the recognition of an immunodiagnostic potential in a herpes virus antigen, the molecular interrelationship of which with cervical tumor cells is described. In addition to the productive infection caused by herpes simplex virus type 2 (HSV-2) we are confronted by latency and, as suggested by recent studies, by cancer. These different types of virus-host cell interactions are discussed at the host, as well as at the cellular level. A defined level of molecular interaction between host and viral gene products must exist if the virus is to co-exist with the host, as is the case in latency and carcinogenesis. The molecular interpretations posit the presence, in the squamous cervical tumor cells, of a product of the expression of the viral genome that has immunodiagnostic potential. The antigen designated AG-4 fulfills these predictions and appears to have immunodiagnostic potential. AG-4 is present in cervical tumor biopsies, but not in normal cervical tissue. It is a structural component of the HSV-2 virion that, in tissue cultures infected with HSV-2, is synthesized preferentially under conditions that prevent the normal replication of the virus. In view of its structural nature it is most probably virus-coded. AG-4 antibody identified in complement fixation assays with antigen prepared in tissue culture, disappears following successful tumor removal and reappears during cancer recurrence. This antibody also potentially identifies those patients with cervical atypia that are at high risk of neoplastic progression. The clinical benefits of the assay are evident.

Trends in electron microscopy of skin

Some trends in electron microscopy of skin have emerged and should be pursued in the future. The fine structure and some basic cellular reaction patterns of epidermal cells are discussed to illustrate the interplay of morphologic, cytochemical, and tracer studies. Intracytoplasmic membranes and secretory granules, lysosomes and endocytic mechanisms, cytomembranes and cell surface specialization are discussed to show how these can be used to arrive at a more meaningful interpretation of structure. Despite all advances, however, a great deal more needs to be done before the details of skin structure are completely elucidated.

Herpesvirus type 2 isolated from cervical tumor cells grown in tissue culture

A herpesvirus has been isolated from spontaneously degenerating cultures of cervical tumor cells grown in vitro. The virus was identified as a type 2 herpesvirus on the basis of biologic properties, including plaque morphology and microtubule formation in infected HEp-2 cells, and of immunologic specificity as determined by neutralization. Herpesvirus antigens and virus particles were not seen in duplicate cultures of viable cervical tumor cells.