Therapeutic periocular vaccination with a subunit vaccine induces higher levels of herpes simplex virus-specific tear secretory immunoglobulin A than systemic vaccination and provides protection against recurrent spontaneous ocular shedding of virus in latently infected rabbits

Rabbits latently infected with herpes simplex virus type 1 (HSV-1) were vaccinated either periocularly or systemically with a subunit vaccine (gB2 + gD2) plus adjuvant or adjuvant alone. Tear films were collected daily to measure recurrent infectious HSV-1 shedding. After systemic vaccination, the latently infected rabbits were not protected against recurrent ocular viral shedding (HSV-1-positive tear film cultures/total cultures) compared with either the systemic or periocular adjuvant controls (systemic vaccination = 49 of 972, 5.0%; systemic control = 46 of 972, 4.7%; periocular control = 43 of 930, 4.6%; P > 0.8). In contrast, latently infected rabbits vaccinated periocularly with the same vaccine had significantly reduced recurrent shedding (20 of 1026, 2.0%) compared with controls (P < 0.001) or systemic vaccination (P = 0.0002). Thus, recurrent HSV-1 shedding was significantly reduced by therapeutic local periocular subunit vaccination but not by therapeutic systemic subunit vaccination. Neutralizing antibody titers in the serum of systemically and ocularly vaccinated rabbits was similar. In contrast, HSV-specific tear secretory immunoglobulin A was significantly higher in the ocularly vaccinated group (P < 0.01). These results strongly suggest that in the rabbit, and presumably in humans, the local ocular (mucosal) immune response is much more important than the systemic immune response for therapeutic protection against recurrent ocular HSV-1. Thus development of a therapeutic vaccine against recurrent ocular HSV-1 should be directed at enhancing the local ocular (mucosal) immune response.     

Interleukin-18 protects mice against acute herpes simplex virus type 1 infection

We examined the effects of interleukin-18 (IL-18) in a mouse model of acute intraperitoneal infection with herpes simplex virus type 1 (HSV-1). Four days of treatment with IL-18 (from 2 days before infection to 1 day after infection) improved the survival rate of BALB/c, BALB/c nude, and BALB/c SCID mice, suggesting innate immunity. One day after infection, HSV-1 titers were higher in the peritoneal washing fluid of control BALB/c mice than in that of IL-18-treated mice. A genetic deficiency of gamma interferon (IFN-gamma), however, diminished the survival rate and the inhibition of HSV-1 growth at the injection site in the mice. Anti-asialo GM1 treatment had no influence on the protective effect of IL-18 in infected mice. IL-18 augmented IFN-gamma release in vitro by peritoneal cells from uninfected mice, while no appreciable IFN-gamma production was found in uninfected mice administered IL-18. Although IFN-gamma has the ability to induce nitric oxide (NO) production by various types of cells, administration of the NO synthase inhibitor NG-monomethyl-L-arginine resulted in superficial loss of the improved survival, but there was no influence on the inhibition of HSV-1 replication at the injection site in IL-18-treated mice. Based on these results, we propose that IFN-gamma produced before HSV-1 infection plays a key role as one of the IL-18-promoted protection mechanisms and that neither NK cells nor NO plays this role.     

Protective vaccination against primary and recurrent disease caused by herpes simplex virus (HSV) type 2 using a genetically disabled HSV-1

The vaccine potential of a mutant herpes simplex virus (HSV) type 1, with a deletion in the glycoprotein H (gH) gene, was evaluated. The virus requires a gH-expressing cell line for multi-cycle growth but can complete a single cycle of infection in noncomplementing cells. Such viruses, termed DISC (disabled infectious single cycle) viruses, should be safe, yet still able to stimulate humoral and cell-mediated responses against a broad range of virus antigens in vaccinated hosts. Prophylactic vaccination of guinea pigs with DISC HSV-1, by ear scarification or direct infection of the vaginal mucosa, afforded a high degree of protection against HSV-2-induced primary genital disease and reduced significantly the frequency of subsequent disease recurrence. There was also a trend toward reduced recurrence following therapeutic vaccination of animals already infected with HSV-2. DISC HSV vaccination, therefore, offers an effective route for control of HSV disease.     

Local expression of tumor necrosis factor alpha and interleukin-2 correlates with protection against corneal scarring after ocular challenge of vaccinated mice with herpes simplex virus type 1

To correlate specific local immune responses with protection from corneal scarring, we examined immune cell infiltrates in the cornea after ocular challenge of vaccinated mice with herpes simplex virus type 1 (HSV-1). This is the first report to examine corneal infiltrates following ocular challenge of a vaccinated mouse rather than following infection of a naive mouse. Mice were vaccinated systemically with vaccines that following ocular challenge with HSV-1 resulted in (i) complete protection against corneal disease (KOS, an avirulent strain of HSV-1); (ii) partial protection, resulting in moderate corneal disease (baculovirus-expressed HSV-1 glycoprotein E [gE]); and (iii) no protection, resulting in severe corneal disease (mock vaccine). Infiltration into the cornea of CD4+ T cells, CD8+ T cells, macrophages, and cells containing various lymphokines was monitored on days 0, 1, 3, 7, and 10 postchallenge by immunocytochemistry of corneal sections. Prior to ocular challenge, no eye disease or corneal infiltrates were detected in any mice. KOS-vaccinated mice developed high HSV-1 neutralizing antibody titers (> 1:640) in serum. After ocular challenge, they were completely protected against death, developed no corneal disease, and had no detectable virus in their tear films at any time examined. In response to the ocular challenge, these mice developed high local levels of infiltrating CD4+ T cells and cells containing interleukin-2 (IL-2), IL-4, IL-6, or tumor necrosis factor alpha (TNF-alpha). In contrast, only low levels of infiltrating CD8+ T cells were found, and gamma interferon (IFN-gamma)-containing cells were not present until day 10. gE-vaccinated mice developed neutralizing antibody titers in serum almost as high as those of the KOS-vaccinated mice (> 1:320). After ocular challenge, they were also completely protected against death. However, the gE-vaccinated mice developed low levels of corneal disease and virus was detected in one-third of their eyes. Compared with KOS-vaccinated mice, the gE-vaccinated mice had a similar pattern of IFN-gamma, but a delay in the appearance of CD4+ T cells, CD8+ T cells, and IL-4-, IL-6-, and TNF-alpha-containing cells. In sharp contrast to those of the KOS-vaccinated mice, no cells containing IL-2 were detected in the eyes of gE-vaccinated mice at any time. Mock-vaccinated mice developed no detectable neutralizing antibody titer and were not protected from lethal HSV-1 challenge.(ABSTRACT TRUNCATED AT 400 WORDS)     

Vaccinating guinea pigs with recombinant glycoprotein D of herpes simplex virus in an efficacious adjuvant formulation elicits protection against vaginal infection

PURPOSE: This study was designed to develop improved criteria for the diagnosis of infective endocarditis and to compare these criteria with currently accepted criteria in a large series of cases. PATIENTS AND METHODS: A total of 405 consecutive cases of suspected infective endocarditis in 353 patients evaluated in a tertiary care hospital from 1985 to 1992 were analyzed using new diagnostic criteria for endocarditis. We defined two "major criteria" (typical blood culture and positive echocardiogram) and six "minor criteria" (predisposition, fever, vascular phenomena, immunologic phenomena, suggestive echocardiogram, and suggestive microbiologic findings). We also defined three diagnostic categories: (1) "definite" by pathologic or clinical criteria, (2) "possible," and (3) "rejected." Each suspected case of endocarditis was classified using both old and new criteria. Sixty-nine pathologically proven cases were reclassified after exclusion of the surgical or autopsy findings, enabling comparison of clinical diagnostic criteria in proven cases. RESULTS: Fifty-five (80%) of the 69 pathologically confirmed cases were classified as clinically definite endocarditis. The older criteria classified only 35 (51%) of the 69 pathologically confirmed cases into the analogous probable category (p < 0.0001). Twelve (17%) pathologically confirmed cases were rejected by older clinical criteria, but none were rejected by the new criteria. Seventy-one (21%) of the remaining 336 cases that were not proven pathologically were probable by older criteria, whereas the new criteria almost doubled the number of definite cases, to 135 (40%, p < 0.01). Of the 150 cases rejected by older criteria, 11 were definite, 87 were possible, and 52 were rejected by the new criteria. CONCLUSION: Application of the proposed new criteria increases the number of definite diagnoses. This should be useful for more accurate diagnosis and classification of patients with suspected endocarditis and provide better entry criteria for epidemiologic studies and clinical trials.     

Molecular methods for the diagnosis of genital ulcer disease in a sexually transmitted disease clinic population in northern Thailand: predominance of herpes simplex virus infection

A multiplex polymerase chain reaction (M-PCR) assay that simultaneously detects the three major causes of genital ulcer disease (GUD), Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus, was used to evaluate swab specimens for 38 sequential patients with GUD at a Thai sexually transmitted disease clinic. Subjects received clinical diagnoses and syndromic treatment. Swab specimens for H. ducreyi cultures and M-PCR were obtained. No H. ducreyi cultures were positive. Of 38 M-PCR specimens, 31 (81.6%) were positive for HSV, 1 (2.3%) for both HSV and T. pallidum, and none for H. ducreyi or T. pallidum alone; 6 (15.8%) were negative for all 3 pathogens. Clinical diagnoses corresponded poorly to M-PCR findings; none of 5 suspected cases of chancroid were positive by M-PCR and none of 1 for syphilis, but 21 of 24 suspected herpes lesions were confirmed by M-PCR. Human immunodeficiency virus infection status was known for 24 of 38 subjects; 11 (45.8%) were seropositive, and all 11 had HSV by M-PCR. HSV appeared to be the most common pathogen overall.     

Effects of the estrous cycle on local humoral immune responses and protection of intranasally immunized female mice against herpes simplex virus type 2 infection in the genital tract

This study demonstrates that the levels of gB-specific IgG and IgA in vaginal washes of mice immunized intranasally (i.n.) with a recombinant adenovirus vector expressing herpes simplex virus (HSV) glycoprotein B (AdgB8) vary inversely with each other and are dependent on the stage of the estrous cycle. Anti-gB IgA titers in vaginal washes were significantly higher during estrus than diestrus or proestrus, whereas specific IgG titers were significantly higher during diestrus than estrus. This was further demonstrated in hormone-treated mice, where progesterone administration induced a diestrus-like state that resulted in elevated specific IgG-to-IgA ratios. Interestingly, unimmunized mice were only susceptible to intravaginal (ivag) infection with HSV-2 during diestrus. Mice immunized i.n. with AdgB8 and given progesterone were protected from a lethal intravaginal HSV-2 challenge, despite the fact that virus replication was present for 4 days postchallenge. Further, high numbers of gB-specific IgA and IgG antibody-secreting cells were present in both the genital tracts and the draining iliac lymph nodes of i.n.-immunized, but not unimmunized, mice 6 days following ivag HSV-2 challenge. These results demonstrate that the levels of specific antibodies in the female genital tract are dependent on the stage of the estrous cycle. Furthermore, i.n. AdgB8 immunization provided a significant level of protection and specific IgA and IgG antibody-secreting cells in the genital tissues during resolution of an ivag infection with HSV-2.     

A role for transforming growth factor-beta1 in the increased pneumonitis in murine allogeneic bone marrow transplant recipients with graft-versus-host disease after pulmonary herpes simplex virus type 1 infection

To gain further insights in the pathogenesis of herpesvirus pneumonia in allogeneic bone marrow transplant recipients, transplanted mice (B10.BR --> CBA) with graft-versus-host disease (GVHD) and control mice (transplanted mice without GVHD and normal CBA mice) were infected intranasally with herpes simplex virus type 1 (HSV-1). When compared with infected control mice, infected allogeneic transplant recipients with GVHD showed increased periluminal mononuclear cell infiltrates. However, infected allogeneic transplant recipients with GVHD showed lower virus content in the lung tissue than infected control mice. High concentrations of transforming growth factor-beta 1 (TGF-beta1) were detected in the bronchoalveolar lavage (BAL) fluid of mock-infected allogeneic transplant recipients with GVHD, which increased slightly after infection. Anti-TGF-beta treatment of allogeneic transplant recipients with GVHD significantly decreased the histological evidence of pneumonitis at day 4 after HSV-1 infection. We conclude that allogeneic transplant recipients with GVHD have (1) increased pneumonia, (2) highly elevated levels of TGF-beta1 in the BAL fluid, and (3) reduced pulmonary virus content after HSV-1 infection. Our data suggest that the newly recognized dysregulation of cytokine (TGF-beta1) production may be more important than the viral load for the increased severity of HSV-1 pneumonia in allogeneic transplant recipients with GVHD.     

An important role for major histocompatibility complex class I-restricted T cells, and a limited role for gamma interferon, in protection of mice against lethal herpes simplex virus infection

Herpes simplex virus (HSV) inhibits major histocompatibility complex (MHC) class I expression in infected cells and does so much more efficiently in human cells than in murine cells. Given this difference, if MHC class I-restricted T cells do not play an important role in protection of mice from HSV, an important role for these cells in humans would be unlikely. However, the contribution of MHC class I-restricted T cells to the control of HSV infection in mice remains unclear. Further, the mechanisms by which these cells may act to control infection, particularly in the nervous system, are not well understood, though a role for gamma interferon (IFN-gamma) has been proposed. To address the roles of MHC class I and of IFN-gamma, C57BL/6 mice deficient in MHC class I expression (beta2 microglobulin knockout [beta2KO] mice), in IFN-gamma expression (IFN-gammaKO mice), or in both (IFN-gammaKO/beta2KO mice) were infected with HSV by footpad inoculation. beta2KO mice were markedly compromised in their ability to control infection, as indicated by increased lethality and higher concentrations of virus in the feet and spinal ganglia. In contrast, IFN-gamma appeared to play at most a limited role in viral clearance. The results suggest that MHC class I-restricted T cells play an important role in protection of mice against neuroinvasive HSV infection and do so largely by mechanisms other than the production of IFN-gamma.