Structure, hemagglutinins, and subgroup position of adenovirus 20, 25, and 28

Virally induced modulation of murine IgG antibody subclasses

The isotypic distribution of murine IgG was examined after infection with several viruses. The results indicate that when a hypergammaglobulinemia was induced by the infection, it was restricted to the IgG2a and, to a lesser extent, to the IgG2b subclasses. In addition, when mice were infected with some viruses concomitantly with the immunization with a soluble protein antigen, a modification in the isotypic distribution of antiprotein antibodies was observed, with a preferential production of IgG2a. These observations indicate that viral infections can actively influence the switch of Igs and selectively stimulate the production of the IgG2a subclass.

Characteristics of mastadenovirus h 8, the causative agent of epidemic keratoconjunctivitis

Adenovirus 8 (Ad 8, strain 1127) has the general structural features of an adenovirus; it produces the genus-specific hexon antigen. The fiber length of 12 nm corresponds to that of other subgenus D adenoviruses. In hemagglutination-inhibition, Ad 8 is related to Ad9 and Ad 15/H9. The slow multiplication, compared to most other subgenus D viruses, was shown not to be caused by an extended growth cycle, but appears to be due to an inefficient virus release into the medium. After restriction analysis with the enzymes Sma I and Bgl II, the typical fragment patterns of species from subgenus D were obtained, while very different patterns emerged from the analysis with Hind III, Bam HI, and Bst E II endonucleases. Several strains of Ad 8 produced more penton-associated toxin than Ad 15/H9 used as reference virus from subgenus D, which could explain the "clumping CPE" caused by Ad 8. Ad 8 toxin was neutralized by antisera from many adenovirus species. The poor virus yield of Ad 8 was not improved by removing soluble viral or cellular substances; all other attempts to improve virus yield by varying the conditions of cell culture also failed.

The fibers of fowl adenoviruses

Purified virions from 14 strains of fowl adenoviruses (FAV) representing 11 serotypes were examined by electron microscopy. Pentons of all strains turned out to have two projections at their penton bases. It is shown that the double fibers also protrude from the intact virion. The length of both fibers was measured on free pentons and is given for each serotype. Double fibers seem to be a common feature of FAV. The serologically unrelated Egg Drop Syndrome (EDS) avian adenovirus strain 127 was confirmed to have single fibers only.

Relationship of human adenoviruses 12, 18, and 31 as determined by hemagglutination inhibition

Adenoviruses 12 and 31, but not Ad18, agglutinate rat blood cells at high titer, providing suitable blood cells be available and a prolonged contact period of virus with the erythrocytes is allowed. Purified virus particles show direct, and virus-free supernatants show direct and indirect, hemagglutination, ie, enhancement of HA by heterologous antiserum. Hemagglutination inhibition with rabbit antisera shows cross-reactions between Ad12 and Ad31 with titers 4--32 times lower than with homologous antigens; Ad18 antisera react with antigens from both of the other serotypes. No cross-reactions were seen with antisera from other adenoviruses. This suggests an antigenic relationship of the three viruses of subgroup IV in their fiber antigen gamma, in addition to the known relation in the hexon (epsilon), which is apparent in cross-neutralization.

Biological and biophysical characteristics of mouse adenovirus, strain FL

Mouse adenovirus, strain FL (MAV), is best propagated in primary rather than secondary cultures of mouse kidney cells. Virus release from the cells into the medium is fairly efficient; the average yield per cell is about 1000 TCID50. Morphological and other biophysical characteristics are those of a typical adenovirus: the icosahedral shell with a diameter of 74 nm, fiber projections of 29 nm length, its localization inside the infected kidney cells, a buoyant density in CsC1 of 1.34 g/ml, inhibition of multiplication by inhibitors of DNA synthesis. The thermostability is higher than that of human adenoviruses, whereas, in contrast to these, MAV is inactivated to a great extent by trypsin. Complete or incomplete hemagglutinin or toxin-like activity were not detected. The virus shows no cross-neutralization with human adenoviruses and a one-side cross-reaction with another murine adenovirus strain K-87. Soluble complement-fixing antigen of MAX exhibits a sedimentation rate of 12S identical to the hexon component of human adenoviruses; both antigens show a partial antigenic relationship in tests with appropriate antisera.