Isolation of JC virus capsomer-like structures from progressive multifocal leukoencephalopathy brain.

Brain tissue from a patient with progressive multifocal leukoencephalopathy (PML) was analyzed by molecular biological and electron-microscopic techniques. Viral DNA was isolated directly from brain tissue, cloned into a plasmid vector, and subjected to restriction endonuclease analysis. The pattern of restriction fragments identified by gel electrophoresis was almost indistinguishable from that of prototype JC virus. By this procedure the etiologic agent of PML in this patient was identified without the isolation of infectious virus. After centrifugal clarification of brain homogenates, high speed centrifugal pellets were studied by electron microscopy. Large numbers of 9-nm polygonal particles, sometimes in paracrystalline arrays, were observed. It was thought likely that these particles were capsomer subunits of 41-43 nm JC virus virions. That the particles were capsomers was supported by negative stain electron microscopy, including reconstruction studies with simian virus 40.

Ultrastructural changes during herpes simplex virus type 2 latency and reactivation in vitro.

An in vitro latency system using herpes simplex virus type 2(HSV2)-infected human embryonic lung cells treated with cytosine arabinoside (ara-C) and incubated at 39.5 degrees after drug removal was used to examine the ultrastructure of the infected cells during (i) ara-C treatment, (ii) the latent period after ara-C removal and temperature elevation, and (iii) reactivation after superinfection with human cytomegalovirus. In the presence of ara-C 'empty', nonenveloped, herpesvirus-like particles were observed in nuclei with fragmented chromatin. After removal of ara-C and temperature elevation, no virions were found. At no time during latent infection were complete virions seen. After superinfection with human cytomegalovirus, extensive synthesis of proteins was suggested by a marked proliferation of rough endoplasmic reticulum, polysomes, and Golgi vesicles. This was followed by the appearance of an electron-dense viral matrix in both the nucleus and cytoplasm and by formation of normal nucleocapsids in the nucleus. The nature of the protein(s) required to reactivate HSV2 is unknown but may involve proteins coded by the virus, the host or both.

Lyme arthritis: correlation of serum and cryoglobulin IgM with activity, and serum IgG with remission.

Forty-eight patients with erythema chronicum migrans (ECM) were studied prospectively for 6 to 18 months. Twenty-six patients had no later symptoms, but 22 subsequently developed Lyme arthritis and 9 of them also experienced neurologic abnormalities. Eighty-seven percent of patients with active ECM followed by subsequent involvement had cryoglobulins containing IgM compared to only 13% of those with active ECM and no later symptoms. The former group also had significantly lower IgG, C3 and C4 levels. Sixty-seven percent of patients still had serum cryoglobulins when neurologic disease was most active, and 45% had them when joint symptoms were most severe, but only 11% continued to have small amounts in remission. The number of patients who continued to have serum cryoglobulins with recurrent attacks of arthritis decreased with time. In contrast, patients always had cryoglobulins in joint fluid, a finding Lyme arthritis shares with rheumatoid arthritis. The cryoprecipitates from 2 of 10 patients contained particles with internal structure, but their viral nature is problematic. All components of antisera obtained from goats and rabbits immunized with cryoglobulins were absorbed by normal human sera. The amount of IgM in cryoglobulins correlated directly with serum IgM, which generally rose during exacerbations and fell during remissions; serum IgG and IgA moved conversely. Thus, IgM was an important correlate of clinical disease activity and IgG or remission.