Glycoprotein H of herpes simplex virus type 1 requires glycoprotein L for transport to the surfaces of insect cells.

In mammalian cells, formation of heterooligomers consisting of the glycoproteins H and L (gH and gL) of herpes simplex virus type 1 is essential for the cell-to-cell spread of virions and for the penetration of virions into cells. We examined whether formation of gH1/gL1 heterooligomers and cell surface expression of the complex occurs in insect cells. Three recombinant baculoviruses, expressing gL1, gH1, and truncated gH1 (gH1t), which lacks the transmembrane region, were constructed. It was shown that recombinant gH1/gL1 and gH1t/gL1 heterooligomers were produced in insect cells. As in mammalian cells, gH1 and gH1t were not detected on the surfaces of insect cells in the absence of gL1. When coexpressed with gL1, recombinant gH1 was displayed on the surfaces of insect cells. Coexpression of gH1t and gL1 resulted in secretion of the gH1t/gL1 complex into the cell culture medium, indicating that gH1t is also transported to the surfaces of insect cells. Our results indicate that the process of folding and intracellular transport of gH1 and gL1 is comparable in insect cells and mammalian cells and that the baculovirus expression system can be used to examine the complex formation and the intracellular transport of gH1 and gL1. The availability of secreted gH1t/gL1 complex offers the opportunity to further investigate the immunological properties of this complex.

Pulmonary dysfunction is common during a cytomegalovirus infection after renal transplantation even in asymptomatic patients. Possible relationship with complement activation.

In 24 patients with a cadaveric renal allograft, serial measurements after transplantation were made of the diffusing capacity for carbon monoxide (DLCO) together with serial measurements of C3d, the stable conversion product of the complement factor C3, and determinations of the anaphylatoxin C3a. Twelve patients were studied during an active cytomegalovirus (CMV) infection, and 12 patients were studied during allograft rejection or during a stable phase after renal transplantation (control subjects). No patients had pulmonary symptoms nor abnormal chest radiographs or arterial blood gas determinations. During an active CMV infection, DLCO was significantly reduced compared with the measurements made during allograft rejection or during a stable phase after renal transplantation. This was true both with (p less than 0.01) and without (p less than 0.01) correction for the hemoglobin concentration. Serum C3d levels were increased in 8 of the 12 patients with a CMV infection, but not in any of the patients in the control group. In 8 patients with a CMV infection, measurements were made of the anaphylatoxin C3a, and were found to be significantly higher than the levels in the control population (p less than 0.01). We conclude that our data are consistent with pulmonary dysfunction in every patient with an active CMV infection. The concomitant findings of complement activation and formation of anaphylatoxins suggest a causal relationship of the complement activation and a decreased DLCO, although further studies are warranted to determine the exact role of complement in the pulmonary events during an active CMV infection after renal transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Legionella pneumophila pneumonia associated with reactivation of cytomegalovirus infection.

Two patients with Legionella pneumophila infection (serogroup 1) associated with a reactivated cytomegalovirus infection are described. Predisposing underlying factors were not evident.