Oral ulcerations associated with disseminated cytomegalovirus (CMV) infection were observed in four patients with AIDS manifestations showing low CD4 counts. Virus cultures of urine and saliva samples were positive for CMV in all cases. The lesions were characterized by a punched-out appearance, non-indurated borders, low bleeding tendency and lack of inflammatory wall. Light microscopy revealed granulation tissue containing "owl's eye" like cells in all specimens. Presence of CMV was confirmed by immunohistochemistry and in situ hybridization. The ulcerations were infiltrated with T-lymphocytes of the helper, suppressor and cytotoxic subset, most were positive for HLA DR. Despite the local invasion with immunocytes and high serum titers of serum antibodies the patients experienced progressive CMV disease.

Immunoelectron microscopy was applied to study the antigenic make-up of human and simian immunodeficiency viruses (HIV, SIV) grown in cells expressing either MHC class I (Molt-3) or MHC class I and II (H9) antigens. A variety of antibodies directed against the surface glycopro­ tein gpl20 of HIV and against MHC class I and II antigens were employed. Consistent with earlier observations on the loss of HIV envelope components, gp120 was only weakly demonstra­ ble on the mature virion. MHC class I determinants were present regularly in small amounts on HIV and SIV. Class II antigens, e.g. HLA-DR were found in high density on HIV and SIV grown in H9 cells, but were absent, as expected, on virus grown in Molt-3 cells. These cellular surface antigens are con­ stituents of the virion. The presence of MHC class II antigens in virus preparations used for diagnostic purposes might explain some of the false positive results in HIV serology. Possible biological implications of these virus associated cellular antigens for the pathogenicity of HIV are discussed.

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The modulatory activity of dextran sulfate with a relative molecular mass of 8 and 500 kDa and pentosan polysulfate with a relative molecular mass of 6 kDa on human T cell surface molecules CD2, CD3, CD4, CD8 and HLA-DR was investigated by analytical flow cytometry. The 500-kDa dextran sulfate induces a complete disappearance of the CD4 and a 50% diminution of CD2 immune reactivity on peripheral blood lymphocytes after a 4-h incubation while the low molecular mass polyanions do not. This modulation of the CD4 immune reactivity includes all CD4 epitopes investigated. It does not correlate with the antiviral effect of polyanions against human immunodeficiency virus infection. The interaction of polyanions with the CD4 presentation is temperature dependent and differs between fresh lymphocytes and immortal cell lines. From our data it can be concluded that mechanisms other than cell surface effects are responsible for the antiviral potency of these drugs. Implications for the modes of antiviral action of sulfated carbohydrates are discussed.