Mary T. Green

Demonstration of HIV-1 and HHV-6 in AIDS-associated retinitis

Using an immunohistochemical technique and monoclonal antisera, HIV-1 and CMV antigens were demonstrated in lesioned areas of retinal tissues from selected AIDS patients. Polymerase chain reaction (PCR) was utilized to detect HIV-1 and HHV-6 DNA sequences in total retinal tissues from these patients. In this study of six eyes from four patients, two of the retinas contained three different viruses, HIV-1, HHV-6 and CMV. To determine whether HIV-1 and HHV-6 DNA sequences were restricted to the intraretinal lesions, normal and lesioned areas were dissected from the retina, DNA was extracted and subjected to amplification using PCR. The results showed that HIV-1 and HHV-6 DNA were restricted to the lesioned areas. All four lesions (from two different patients) utilized in this study showed the presence of CMV antigens immunohistochemically. The combination of viruses present in each lesion was either HIV-1 and CMV or HHV-6 and CMV. Two of four lesions contained HIV-1 and CMV; a third lesion showed the presence of HHV-6 and CMV. The fourth lesion contained only CMV antigens.

Frequency of dual infections of corneas with HIV-1 and HHV-6

In the current study, 35 pairs of corneas from asymptomatic carriers of HIV-1 and ten pairs from AIDS patients were analyzed for the presence of HIV-1 and HHV-6. The tissues were evaluated for viral antigens, transcripts, DNA sequences and intact and infectious virus. Three corneas from two asymptomatic carriers of HIV-1 and three corneas from two AIDS patients were culture positive for HIV-1. One of the three HIV-1 positive corneas from an asymptomatic HIV-1 carrier also was culture positive for HHV-6. Two of the tissue culture positive corneas from asymptomatic HIV-1 carriers and two from AIDS patients also tested positive for HIV-1 transcriptional activity by in situ hybridization. The label denoting the transcriptional activity was limited to stromal keratocytes. Most significantly, we were able to demonstrate the presence of HIV-1 particle(s) in sections and cultured PBMC from one of the HIV-1 culture positive corneas. PBMC from the same cornea also contained herpes virus particles. This report strengthens our earlier findings that HIV-1 and HHV-6 can invade corneal tissue, which emphasizes the importance of vigorous screening of corneal donors, specifically donors with HIV-1 exposure.

The incidence of HIV-1 and HHV-6 in corneal buttons

Twenty pairs of corneas from asymptomatic carriers of HIV-1 and seven pairs from AIDS patients were analyzed for the presence of HIV-1 and HHV-6 antigens, viral transcripts, DNA sequences, and intact and infectious particles. Although serum from all donors was positive for both HIV-1 and HHV-6 antibody by Western blot analysis, only one cornea from an asymptomatic carrier of HIV-1 was positive for HIV-1 and HHV-6. The cornea was positive when tested by tissue culture, PCR, in situ hybridization, and electron microscopy. There was no tear film contamination. These results suggest that HIV-1 and HHV-6 may be capable of invading corneal tissue.

Morphological and ultrastructural changes induced in corneal epithelial cells by HIV-1 and HHV-6 in vitro.

PURPOSE The purpose of this study was to determine whether HIV-1 and HHV-6 are capable of infecting and inducing morphological and ultrastructural changes in corneal epithelial cells in vitro. METHODS Primary and transformed corneal epithelial cell cultures were infected with HIV-1 or HHV-6 in vitro and analyzed for the presence or absence of viral antigens, DNA sequences, viral particles and inclusions. RESULTS HIV-1 antigens were detected in 8% of the HIV-1 infected cells and early HHV-6 antigens were present in 12% of the HHV-6 infected cells. The presence of viral DNA sequences in the cultures confirmed these findings. Cells infected with HIV-1 morphologically were not different from uninfected cells, whereas the morphology of HHV-6 infected cells was very similar to cells infected with other human herpesviruses. Cytoplasmic tubuloreticular inclusions were detectable in corneal epithelia cells infected with HIV-1 and intact viral particles were visible only in PBMC used to recover HIV-1 from these cultures. Viral inclusions were also observed in corneal epithelial cells infected with HHV-6. CONCLUSION These data indicate that HIV-1 and HHV-6 are capable of infecting corneal epithelial cells in vitro, but the viruses are not entering these cells via CD4 or galC receptors. This basic information is important in determining the pathogenic mechanism(s) involved in the development of AIDS-associated corneal disorders.

Effect of immunization and immunosuppression on induced ocular shedding and recovery of herpes simplex virus in infected rabbits

Immunization and immunosuppression were evaluated during latent ocular herpes simplex virus, type 1 (HSV-1) infection in the rabbit, using the following parameters: (1) ability to recover virus from preocular tearfilm cultures; (2) reactivation of latent infection by direct electrical stimulation; and (3) recovery of virus from latently infected ganglia by whole-cell co-cultivation. Immunization prior to ocular inoculation of virus significantly reduced both the titer of virus shed into the tearfilm and the duration of virus shedding during primary ocular infection. Half of the non-immunized control rabbits died secondary to virus encephalitis, whereas none of the immunized rabbits died. The immunized rabbits could not be induced to shed virus by electrically stimulating the trigeminal ganglion directly. Immunosuppression of latently infected rabbits with high-dose cyclophosphamide (300 mg kg-1) enhanced virus shedding in the tearfilm and increased mortality due to viral encephalitis. Low-dose cyclophosphamide immunosuppression (40 mg kg-1) did not increase mortality because of viral encephalitis. Tearfilm virus shedding secondary to electrical induction in high-dose and low-dose cyclophosphamide animals was higher than that of control, non-immunosuppressed animals.

Study of HSV-1 DNA species from trigeminal ganglia of rabbits during acute and latent infections

Recurrent herpetic keratitis remains a major cause of corneal blindness in developed countries. A fundamental unanswered question regarding herpes simplex virus infection concerns the relationship between the virus and host cell DNA during latency. In the present study DNA was extracted from trigeminal ganglia during both acute and latent infection following ocular inoculation. Extracted, purified DNA was utilized for transfection and for hybridization studies using a 32P-labeled HSV-1 DNA probe. DNA extracted during acute infection was complete, linear and non-integrated. Autoradiographic patterns of DNA isolated during latent infection were suggestive of two separate DNA species.

Chapter 20 HIV-1 and HHV-6 infections of human retina and cornea

Publisher Summary More than 110,000 Americans have died and more than one million are believed to be infected with the human immunodeficiency virus (HIV-1). This chapter discusses the human immunodeficiency virus type I that has been identified in retinal tissue of the AIDS patients. Eye infection, a common complication of AIDS, strikes as many as 98% of all people infected with HIV-1. Approximately 50–80% of individuals with HIV-1 infection experience significant visual loss prior to death, further complicating an already devastating disease process. Thousands of the affected are young adults and teenagers; perhaps some of the saddest cases are seen in infants and very young children who are victims of this deadly disease. It was also reported that the isolation of HIV-1 and HHV-6 from corneas of asymptomatic are from HIV-1-positive donors, suggesting that corneal tissue might be capable of supporting HIV-1 and HHV-6 infection.