Macrophage migration inhibition as a correlate of cell-mediated immunity to herpes simplex virus type 2 in mice

Mice inoculated intraperitoneally or intravenously with herpes simplex virus type 2 (HSV-2) develop a focal necrotizing hepatitis. The livers show expanding foci of necrosis and increasing virus content during the first days of the infection with maximal titers achieved on day 3. The clearance of virus from the organ is manifest from day 4 onward with the most dramatic fall in virus content occurring between days 4 and 5. The development of immunity during the course of infection was assessed by adoptive transfer experiments and by measuring macrophage migration inhibition factor (MIF) production of spleen cells in an indirect agarose microdroplet assay. Antiviral activity of adoptively transferred spleen cells was demonstrable from day 4 of the infection when 50 X 10(6) spleen cells were transferred into recipient mice infected 24 h previously. MIF production in spleen cell cultures stimulated with antigen was found to be specific in that activity was only detected in cultures derived from immune mice and stimulated with the virus antigen. The response was found to be antigen-dose and cell-number dependent. Significant MIF production was demonstrable in spleen cell cultures derived from mice 3 days after the infection, i.e. concomitant with the initiation of recovery and before antiviral activity can be detected in transfer experiments. It is suggested that a delayed type hypersensitivity reaction with lymphokine production leading to recruitment of macrophages and their retention and activation in the foci of infection may be a major factor in the recovery from the infection.     

Application of shRNA-containing herpes simplex virus type 1 (HSV-1)-based gene therapy for HSV-2-induced genital herpes

HSV-1-based vectors have been widely used to achieve targeted delivery of genes into the nervous system. In the current study, we aim to use shRNA-containing HSV-1-based gene delivery system for the therapy of HSV-2 infection. Guinea pigs were infected intravaginally with HSV-2 and scored daily for 100 days for the severity of vaginal disease. HSV-2 shRNA-containing HSV-1 was applied intravaginally daily between 8 and 14 days after HSV-2 challenge. Delivery of HSV-2 shRNA-containing HSV-1 had no effect on the onset of disease and acute virus shedding in animals, but resulted in a significant reduction in both the cumulative recurrent lesion days and the number of days with recurrent disease. Around half of the animals in the HSV-2 shRNA group did not develop recurrent disease 100 days post HSV-2 infection. In conclusion, HSV-2 shRNA-containing HSV-1 particles are effective in reducing the recurrence of genital herpes caused by HSV-2.     

Concanavalin A-induced interferon gamma production by murine spleen cells and T cell lines. Lack of correlation with Lyt 1,2 phenotype

Concanavalin A(Con A)-induced interferon-gamma (IFN gamma) production by resting or preactivated murine spleen cells negatively selected with monoclonal antibodies specific for Lyt 1,2 antigens plus complement (C) and by interleukin 2(IL-2)-dependent T cell lines of different Lyt phenotype was studied. The data show that most of the IFN-gamma produced upon stimulation of resting spleen cells was a product of Lyt 1+2+ cells. Lyt 1-2+ cells were negative for IFN gamma production. When spleen cells that had been preactivated for 3 days with Con A were restimulated with Con A, Lyt 1+2+, Lyt 1+2- as well as Lyt 1-2+ cells produced IFN gamma in a relationship of approximately 5:3:1. In both cases the picture remained unaltered independently when the supernatants were harvested after 1, 3 or 5 days. Furthermore, two IL-2 dependent T cell lines were studied in regard to Con A-induced IFN gamma production. Line 1.3 was Thy 1+, Lyt 1-2+, whereas line 20.9. was Thy 1+, Lyt 1+2-. Both lines produced initially high titers of IFN gamma upon stimulation with Con A. After prolonged passage in vitro, however, they progressively lost the capacity to produce IFN gamma.     

Acute and latent herpes simplex virus neurological disease in mice immunized with purified virus-specific glycoproteins gB or gD

Groups of 5-week-old BALB/c mice were immunized intraperitoneally with approximately 10 micrograms of purified alum-precipitated glycoprotein gB or gD of either herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) origin. Control mice received injections of alum-precipitated 1% bovine serum albumin (BSA). Following a second immunization 4 weeks later, seroconversion was confirmed by demonstrating the presence of glycoprotein-specific antibody by immune precipitation. All animals were challenged with lethal doses of either HSV-1 or HSV-2 by footpad inoculation and assessed for acute virus-induced neurological disease and the development of ganglionic latency. Whereas 70% of control (BSA-immunized) HSV-1-infected animals developed ascending myelitis and died, 100% of mice immunized with either gB-1, gB-2, gD-1, or gD-2 antigens remained free of clinical illness and survived HSV-1 challenge. In contrast, gB-1-or gB-2-immunized mice were not protected against acute HSV-2-induced neurological disease and showed a mortality rate of 60-90% (equivalent to that seen in controls), although mean survival times were prolonged. However, significant protection against HSV-2 challenge was observed with gD-1 or gD-2 immunization. When sacral ganglia were removed from surviving mice 9-12 months after virus challenge, latent virus was detected in all gB- or gD-immunized animals, although the extent of latent infection was restricted. These results provide evidence that glycoprotein gD might be superior to glycoprotein gB as an immunogen for the control of acute HSV-1 and HSV-2 neurological disease in mice. However, neither glycoprotein prevents ganglionic latency, the source of virus for recurrent herpesvirus infections.     

Flip-flop in the Lyt 2 phenotype of T cells from radiation chimaeras between Thy 1 congenic donor and recipient mice.

We present further evidence that T helper cells change their surface phenotype from Lyt 2- to Lyt 2+, after secondary adoptive transfer. Chimaeras were established with Lyt 2- spleen cells from normal, or carrier-primed A-Thy 1a donors and irradiated, A-Thy 1b recipients. Despite efficient depletion of Lyt 2+ cells from the initial donor, in the fluorescence-activated cell sorter, the majority of chimaeric T cells expressed Lyt 2 and were resistant to monoclonal Thy 1.2 alloantibody and complement treatment. In functional studies, the T helper activity of chimaeras, reconstituted with carrier-primed spleen cells, was present in both Lyt 2+ and Lyt 2- subsets.     

Efficacy of Kakkon-to,a traditional herb medicine,in herpes simplex virus type 1 infection in mice

Kakkon-to is one of the representative traditional herb medicines (Kampo formulae) and has been used historically for the treatment of infectious diseases in China and Japan. The efficacy of this preparation was characterised using a cutaneous herpes simplex virus type 1 (HSV-1) infection in mice as a model for human viral infection. Kakkon-to at a dose corresponding to human use reduced significantly the mortality of HSV-1-infected mice and localised skin lesions. Delayed type hypersensitivity (DTH) response to HSV-1 antigen was significantly stronger in treated mice than in untreated mice. However, no histopathological difference was noted in the skin lesions between treated and untreated mice except for the size of the lesions. Kakkon-to did not inhibit the growth of HSV-1 in vitro. Natural killer cell activity, natural cytotoxic killer cell activity, and the population of T-cell subsets in spleen cells of infected mice were not affected by the drug. Kakkon-to did not augment interferon induction and anti-HSV-1 antibody production, nor increased cytokine levels such as interleukin-1α, interleukin-2, interferon-γ, and tumour necrosis factor-α in sera of infected mice. Thus, Kakkon-to induced strong DTH to HSV-1 in infected mice, which may have caused localisation of skin lesions and reduction in the mortality of treated mice. © 1995 Wiley-Liss, Inc.     

Do L3T4+ T cells act as effector cells in protection against influenza virus infection

This study aimed to analyse the roles of Lyt 2+ and L3T4+ memory T-cell subpopulations in murine influenza infection. Previous work has shown that Lyt 2+ cytotoxic T-cell (Tc) clones can adoptively transfer protection. We therefore wished to see whether L3T4+ (Th) cells could also act as protective effector cells. Donors for adoptive cell transfer were thymectomized mice, depleted in vivo of either Lyt 2+ or L3T4+ T cells with monoclonal antibodies (MAb) and then infected with influenza virus (A/X31). Primed spleen cells, after removal of the B cells, were transferred into irradiated hosts infected simultaneously or persistently with a heterologous influenza virus and the effect on lung virus replication determined. Depletion of L3T4+ T cells suppressed the formation of IgG antibodies after influenza virus infection, indicating significant depletion of T-helper function. Yet Lyt 2+ class I MHC-restricted Tc cells were effectively primed in these mice, albeit to half the normal level. Adoptive transfer of the Lyt 2+ memory T cells cleared virus in a persistent infection within 6 days. Spleen cells selected for L3T4+ T cells cleared virus within 21 days of transfer in a simultaneous infection and reduced viral titres in a persistent infection, but not as effectively as L3T4+-depleted spleen cells. Although no Lyt 2+ cells were detected by fluorescence staining in Lyt 2+-depleted spleens, we could detect low levels of class I MHC-restricted influenza-specific Tc memory cells in host spleens following influenza infection. Therefore, whether the early viral clearance is solely due to L3T4+ T cells is not clear. Lyt 2+ memory T cells appear more efficient in this respect than L3T4+ memory T cells.     

Expression of the herpes simplex virus type-2 major DNA-binding protein (ICP8) gene in COS-1 cells

By the use of an SV40 origin of replication plasmid vector and the COS-1 cell system, expression of the gene encoding the herpes simplex virus type-2 (HSV-2) major DNA binding protein (ICP8) has been achieved. The HSV-2 4.5 kb BgIII 0 DNA fragment containing the ICP8 coding region was inserted into the plasmid vector pSVOd containing the SV40 origin of replication. Transfection of COS-1 cells by the resultant recombinant plasmid (pSVOd20), and subsequent multiplication of this plasmid, led to the production of the HSV-2 major DNA binding protein in sufficient quantities to allow its detection with either monoclonal or polyclonal antibodies as well as sera taken from HSV-2 patients.     

Improvement of herpetic stromal keratitis with fumaric acid derivate is associated with systemic induction of T helper 2 cytokines

Fumaric acid derivates have been shown to stimulate T helper-2-cytokines (interleukin (IL)-4, -5) without affecting the T-helper-1-cytokine (IL-2, interferon (IFN)-gamma)-response. Herein, the influence of systemic treatment with the fumaric acid derivate dimethylfumarate (DMF) on the secretion of T helper-cytokines and the development of HSV-1 stromal keratitis (HSK) was studied in mice. The corneas from BALB/c mice were infected with 10(5) PFU of HSV-1 (KOS strain). While one group of mice was treated intraperitoneally with PBS, another group of mice received DMF at 15 mg/kg of body weight. Expression of IL-2, -4, -10 and IFN-gamma was analysed in HSV-1 activated lymphocytes by ELISA. The severity of epithelial and stromal herpetic keratitis was investigated clinically. Corneas were studied for the inflammatory cell infiltration, and the CD3-, CD4- and CD8-positive cells were analysed by immunohistochemistry. The IL-2, -4, 10 and IFN-gamma content was measured in the corneas. Virus replication in the eyes was analysed by a plaque-assay. The DTH-response, the HSV-specific T cell proliferation and the serum neutralizing antibody-titres were investigated. DMF increased IL-4 and IL-10, but not IL-2 and IFN-gamma, secretion in activated lymphocytes from the spleen. Incidence and severity of stromal HSV-1 keratitis was reduced in the DMF group (P < 0.01). In the corneas from DMF-treated mice, the numbers of CD3+ and CD4+ cells were decreased and IL-4 was increased. Severity of epithelial disease and the virus-clearance from the eyes did not differ between the PBS and DMF group of mice. DTH, HSV-specific T cell proliferation and the neutralizing antibody-titres were not impaired. DMF increased the T helper-2-cytokine secretion in activated lymphocytes. After corneal HSV-1 infection, corneas from DMF treated mice had increased IL-4 content. This is associated with an improvement of herpetic stromal keratitis and reduced corneal T cell infiltration. DMF did not impair the systemic antiviral response.     

Mediation of immunity to Eimeria vermiformis in mice by L3T4+ T cells.

Immunity to infection with Eimeria vermiformis was transferred in NIH mice by both the nylon wool-adherent (B-cell-enriched) and nonadherent (T-cell-enriched) fractions of lymphocytes (spleen and mesenteric lymph node) taken from infected donors. Transfer was more variable with the adherent fraction, and when contaminating T cells were removed by treatment with anti-Thy1 monoclonal antibody (MAb) and complement, this fraction lost all protective activity. The protective effect of T-cell-enriched populations of mesenteric lymphocytes was abrogated by treatment with anti-L3T4 MAb and complement in vitro before transfer or by opsonization with this MAb in vitro before intravenous inoculation into recipients. Similar treatments of cells with anti-Lyt2 MAb did not have this effect, confirming that Thy1+ L3T4+ cells mediate the adoptive transfer of immunity to E. vermiformis. Thy1+ L3T4+ cells were also shown to limit the replication of E. vermiformis in primary infections: mice depleted of this subset (by thymectomy followed by intravenous injection of anti-L3T4 MAb) passed greater numbers of oocysts over a longer period of time than did mice similarly depleted of Lyt2+ cells.     

Activity of the keggin polyoxotungstate pm-19 against herpes simplex virus type 2 infection in immunosuppressed mice: Role of peritoneal macrophage activation

The in vivo antiviral activity of the Keggin polyoxotungstate PM-19 [K₇(PTi₂W₁₀O₄₀) · 6H₂O] against herpes simplex virus type 2 (HSV-2) was investigated in mice immunosuppressed by cyclophosphamide (CY). When PM-19 was administered intraperitoneally to immunosuppressed mice for 3 days (once daily) starting at the time of infection, it prevented death due to HSV-2 encephalitis in a dose-dependent manner (10–25 mg/kg). The in vivo anti-HSV-2 activity of PM-19 was superior to that of acyclovir. Intraperitoneal administration of PM-19 to the immunosuppressed mice significantly increased the number of peritoneal cells, especially macrophages. PM-19 did not stimulate interferon-inducing activity or natural killer cell activity, but markedly enhanced peritoneal macrophage functions: (1) phagocytic activity as assessed by measuring the amount of⁵¹Cr-labeled sheep red blood cells taken into the macrophages, and (2) extrinsic antiviral activity as monitored by reduction in the numbers of plaque formed upon cocultivation of HSV-2-infected HEL cells with the macrophages. These results point to the role of peritoneal macrophage activation in the activity of PM-19 against HSV-2 infection in immunosuppressed mice.     

During recovery from cytomegalovirus infection T-lymphocyte subsets become selectively responsive to activation and have depressed interleukin 2 (IL2) secretion and IL2 receptor expression

The ability to induce lymphocyte activation with Concanavalin A (Con A) was suppressed in spleen cell cultures derived from BALB/c mice acutely infected with murine cytomegalovirus (MCMV) when compared to cultures derived from control, uninfected mice. This immunosuppression was observed as a reduced incorporation of 3H-thymidine in the lymphocyte proliferative response to Con A, was highly correlated with reduced secretion of interleukin 2 (IL2), and could not be augmented by addition of exogenous IL2. The degree of suppression of both the proliferative response and IL2 secretion was directly dependent on the infecting virus dose and on the time post-infection. At weekly intervals during infection, fluorescein-labeled monoclonal antibodies to various T-lymphocyte surface markers were used to stain spleen cells from control or MCMV-infected mice before or after Con A activation. Analysis of stained spleen cells by flow cytometry revealed several unusual responses to activation signals in lymphocytes derived from mice with acute MCMV-induced immunosuppression. At 4 days post-infection T-lymphocytes of each subset [Thy 1.2 (pan T), L3T4 (T-helper/inducer), Lyt 2 (T-cytotoxic/suppressor) and Lyt 1 (subset of Thy 1.2)] were each present in the spleen but each was in reduced percentage of the total spleen T cell population compared to control (52% to 75% of controls). At this time post-infection these cells were non-responsive to Con A activation as shown by inability to induce 3H-thymidine uptake, IL2 secretion or IL2 responsiveness and an inability to demonstrate an IL2 receptor-positive (IL2R+) population. By 11 days post-infection all tested subsets of T-lymphocytes (Thy 1.2+, L3T4+, Lyt 2+ and Lyt 1+) were in normal control range in fresh spleen. However, only Thy 1.2+L3T4+ (T-helper/inducer) cells were responsive to Con A activation. 3H-thymidine uptake and IL2 secretion were at levels of about 60% of the control but, surprisingly, cells were unresponsive to addition of exogenous IL2 and few, if any, of these cells were found to express IL2 receptors. By 18 days post-infection, when 3H-thymidine uptake could be induced at control level, Thy 1.2+, L3T4+, and Lyt 2+ (T-cytotoxic/suppressor) cells were each responsive to Con A activation at levels comparable to control but Lyt 1+ and IL2 R+ cells were still substantially suppressed (ca. 35% to 40% of control value). Detection of Lyt 1+ subset and IL2 R+ cells after Con A activation did not near control levels until very late in the recovery process (day 25).(ABSTRACT TRUNCATED AT 400 WORDS)     

Function,target-cell preference and cell-surface characteristics of herpes-simplex virus type-2-induced non-antigen-specific killer cells

Wild-type and congenitally athymic nude mice injected with herpes-simplex virus type 2 (HSV 2) responded with a local outburst of non-antigen-specific killer cells masking any virus-specific response. Cytolytic activity could be assayed on mouse-tumor cell lines and on syngeneic or allogeneic non-transformed cells from various sources. Some of the tumor cell lines and proteose-peptone-induced peritoneal exudate cells were lysed more efficiently after infection with either HSV 2, vaccinia or influenza A virus. Preference for virus-infected target cells was already expressed 24 hours after HSV -2 injection. Killing activity was not H-2- restricted, not complement- or immunoglobulin-dependent and did not involve Fc receptors. The cytotoxic cells were non-adherent and could be shown to express Thy1, Quat4, and Quat5 cell-surface antigens. They lacked immunoglobulin and Lyt1 : Lyt2,3 determinants. The functional and serological characteristics identify the HSV-2-induced cytolytic cells as natural killer (NK) cells. The potential importance of this cell population for natural resistance will be discussed.     

Persistent expression of CD94/NKG2 receptors by virus-specific CD8 T cells is initiated by TCR-mediated signals

Subsets of CD8 T cells express receptors that are critical in regulating the activity of NK cells. To characterize the expression of these receptors on CD8 T cells we made use of transgenic mice that express a H-2Kb restricted TCR specific for the immunodominant epitope located within the HSV-1 glycoprotein B (gB). Few naive gB-specific T cells express Ly49 or CD94/NKG2 receptors. Following acute infection of C57BL/6 mice with either HSV-1 or a recombinant influenza virus that encodes the gB determinant, gB-specific T cells showed a dramatic upregulation of CD94/NKG2 receptors. Moreover, gB-specific CD8 T cells that expressed CD94/NKG2 receptors were also found to express another NK receptor, KLRG1. We established that while Ag-stimulated gB-specific CD8 T cells primarily express inhibitory isoforms of CD94/NKG2 receptors, these cells remain capable of producing gammaIFN upon peptide stimulation. While peak CD94/NKG2 expression on gB-specific cells was reached 2-3 days following infection, it remained elevated beyond 60 days post-infection with either HSV-1 or a gB-expressing recombinant influenza virus. The data imply that the prolonged expression was not due to persistence of replicating virus and suggest that while recognition of the cognate Ag is necessary to trigger expression of CD94/NKG2 receptors, it is not required for their continued expression on memory T cells.     

The lack of RNA-dependent protein kinase enhances susceptibility of mice to genital herpes simplex virus type 2 infection

Mice deficient in RNA-dependent protein kinase (PKR-/-) or deficient in PKR and a functional 2',5'-oligoadenylate synthetase (OAS) pathway (PKR/RL-/-) are more susceptible to genital herpes simplex virus type 2 (HSV-2) infection than wild-type mice or mice that are deficient only in a functional OAS pathway (RL-/-) as measured by survival over 30 days. The increase in susceptibility correlated with an increase in virus titre recovered from vaginal tissue or brainstem of infected mice during acute infection. There was also an increase in CD45+ cells and CD8+ T cells residing in the central nervous system of HSV-2-infected PKR/RL-/- mice in comparison with RL-/- or wild-type control animals. In contrast, there was a reduction in the HSV-specific CD8+ T cells within the draining lymph node of the PKR/RL-/- mice. Collectively, activation of PKR, but not of OAS, contributes significantly to the local control and spread of HSV-2 following genital infection.     

Evaluation of mixed infection cases with both herpes simplex virus types 1 and 2

Herpes simplex virus type 1 (HSV-1) is isolated principally from the upper half of the body innervated by the trigeminal ganglia whereas herpes simplex virus type 2 (HSV-2) is generally isolated from the lower half of the body innervated by the sacral ganglia. However, recent reports suggest that HSV-1 and HSV-2 can each infect both the upper and lower half of the body causing a variety of symptoms and there is a possibility that HSV-1 and HSV-2 infections can occur simultaneously with both causing symptoms. HSV type in clinical isolates from 87 patients with genital herpes and 57 with ocular herpes was determined by the polymerase chain reaction (PCR), and six cases of mixed infection with both HSV-1 and HSV-2 were identified. Of the six cases, three were patients with genital herpes and three were ocular herpes patients. Analysis of the copy number of the HSV-1 and HSV-2 genome by a quantitative real time PCR demonstrated that HSV-1 was dominant at a ratio of approximately 100:1 in the ocular infections. In contrast, the HSV-2 genome was present at a 4-40 times higher frequency in isolates from genital herpes patients. There was no obvious difference between the clinical course of mixed infection and those of single HSV-1 or HSV-2 infections. This study indicated that the frequency of mixed infection with both HSV-1 and HSV-2 is comparatively higher than those of previous reports. The genome ratio of HSV-1 and HSV-2 reflects the preference of each HSV type for the target organ.     

In vitro primary induction of T cells mediating delayed footpad reaction and acquired cellular resistance to Listeria monocytogenes

We established an in vitro system generating L. monocytogenes-specific T cells primarily from unprimed spleen cells of mice. Normal spleen cells were cultured for 5 days in the presence of L. monocytogenes in vitro. Viable cells were harvested and assessed for their capacity to confer acquired cellular resistance (ACR) and delayed footpad reaction (DFR) upon local passive transfer to naive syngeneic recipient mice. When normal spleen cells were stimulated with viable L. monocytogenes, the viable cells that were recovered after 5 days of culture conferred a high level of ACR and DFR. Negative selection revealed that the effector cells obtained in primary in vitro culture were Thy 1+, L3T4+, Lyt2- cells. T cells mediating ACR could not be generated in the culture of normal spleen cells with heat-killed bacteria; however, cells mediating only DFR were generated in the presence of a large number of killed L. monocytogenes. The expression of DFR and ACR by T cells generated in this primary culture system was Listeria-specific; reactions were not observed against unrelated bacterial antigens including S. typhimurium, S. aureus, E. coli and PPD. FACS analysis of the cells in culture showed that L3T4+ and Lyt2- T cells were being enriched during culture. The primary generation of antigen-specific T cells in vitro was also possible with spleen cells from NTx mice but not with cells from nude mice, suggesting the presence of Listeria-specific precursors in NTx mice.     

Growth of herpes simplex virus in epidermal keratinocytes determines cutaneous pathogenicity in mice

Herpes simplex viruses (HSV)-1 and -2 isolated from genital lesions were examined for cutaneous pathogenicity and its correlation with cellular tropism. HSV-1 caused vesiculation, erosion/ulcer, and zosteriform lesions successively, but skin lesions of HSV-2 developed without vesiculation in some mice, and with statistically significantly less frequent vesiculation than HSV-1. Thus, the virological type of HSV was correlated with its cutaneous pathogenicity. The growth characteristics of HSV-1 and -2 were compared in cultured human embryonic lung (HEL) fibroblasts, human lung cancer A549 cells, human neonatal epidermal keratinocytes, human neonatal dermal fibroblasts, HeLa cells, and Vero cells. HSV-2 produced plaques that were 72% times the size of HSV-1 plaques in epidermal keratinocytes but 230%-500% the size in the other cells. The difference between HSV-1 and -2 in the ratio of plaque size to virus yield in epidermal keratinocytes was much larger (502 times) than the ratio of the other cells (5.57-28.8 times). Keratinocytes are the major constituent of the epidermal layer of the skin and the cells in which vesiculation and erosion/ulceration occur histologically. Therefore, the smaller spread of HSV-2 in keratinocytes of the epidermal layer and the greater spread in other cells of the dermal layer might reflect its lesser invasiveness in the epidermal layer despite larger invasiveness in the dermal layer, which is reflected in the low incidence of erosion/ulcer of the skin compared to HSV-1. Thus, the growth of HSV in epidermal keratinocytes appeared to correlate with the cutaneous pathogenicity causing vesiculation in the skin.     

A reproducible method for the optimum infection of human mononuclear cells and lymphoid cell lines by herpes simplex virus type I

Parameters for the infection of human mononuclear cells (MNC) with herpes simplex virus type 1 (HSV-1) were investigated and a procedure was established which resulted in a reproducible optimum number of cells expressing virus-specific cell surface antigens The number of cells infected was independent of the sex of the donor and independent of whether the donor was HSV- seropositive or -seronegative. On the average 18±6% of HSV-infected MNC from any given donor expressed HSV-specific cell surface antigens. When the standard procedure was applied to a variety of lymphoid cell lines, a high percentage of cells of both B and non-T/non-B lines expressed HSV-specific cell surface antigens, whereas T-cell lines appeared resistant to HSV infection.     

Role of Fas/FasL signaling in regulation of anti-viral response during HSV-2 vaginal infection in mice

Fas receptor–Fas ligand (FasL) signaling is involved in apoptosis of virus-infected cells but increasing evidence accumulates on Fas receptor as a mediator of apoptosis-independent processes such as induction of activating and pro-inflammatory signals. In this study, we examined the role of Fas/FasL pathway in regulation of anti-viral response to genital HSV-2 infection using a murine model of HSV-2 infection applied to C57BL6/J, B6. MRL-Faslpr/J and B6Smn.C3-Faslgld/J mice. HSV-2 infection of Fas- and FasL-deficient mice led to decreased migration of IFN-γ expressing NK cells and CD4+ T cells, but not of γδ T cells, into the vaginal tissue. The vaginal tissues of HSV-2 infected Fas- and FasL-deficient mice showed increased production of IL-10, followed by low expression of the early CD69 activation marker on CD4+ and CD8+ T cells and increased numbers of regulatory T cells (Tregs). Experiments in co-cultures of CD4+ T cells and bone marrow derived dendritic cells showed that lack of bilateral Fas–FasL signaling led to expansion of Tregs and increased production of IL-10 and TGF-β1. Our results demonstrate that Fas/FasL can regulate development of tolerogenic dendritic cells and expansion of Tregs early during HSV-2 infection, which further influences effective anti-viral response.