Protection against herpes simplex virus infection in mice by Corynebacterium parvum

Pathogenesis of malaria and clinically similar conditions

There is now wide acceptance of the concept that the similarity between many acute infectious diseases, be they viral, bacterial, or parasitic in origin, is caused by the overproduction of inflammatory cytokines initiated when the organism interacts with the innate immune system. This is also true of certain noninfectious states, such as the tissue injury syndromes. This review discusses the historical origins of these ideas, which began with tumor necrosis factor (TNF) and spread from their origins in malaria research to other fields. As well the more established proinflammatory mediators, such as TNF, interleukin-1, and lymphotoxin, the roles of nitric oxide and carbon monoxide, which are chiefly inhibitory, are discussed. The established and potential roles of two more recently recognized contributors, overactivity of the enzyme poly(ADP-ribose) polymerase 1 (PARP-1) and the escape of high-mobility-group box 1 (HMGB1) protein from its normal location into the circulation, are also put in context. The pathogenesis of the disease caused by falciparum malaria is then considered in the light of what has been learned about the roles of these mediators in these other diseases, as well as in malaria itself.

Protection and therapy of experimental herpesvirus infections in mice with immunomodulating Propionibacterium avidum KP-40 and/or acyclovir

Protection and therapy of NMRI mice with experimental herpes virus (HSV-1) encephalitis were investigated using heat-killed, lyophilized Propionibacterium avidum KP-40 (PA) and/or the herpes-specific antiviral substance acyclovir (ACL) as immunomodifier. Poly I:C as a potent macrophage activator was used as a reference compound for PA. Survival of experimental HSV-1 infections during 18 days following the inoculation of viruses was used for the evaluation of the effects of immunotherapy. The applied model of HSV-1 infection resulted in a mortality of about 87% of NMRI mice at 7-16 days following the inoculation of the virus. Treatment with ACL or Poly I:C at the day of HSV-1 infection resulted in a lowering of the mortality rate to about 40% (p < 0.05). PA applied 4 days before HSV-1 infection lowered the mortality rate to 27%, while treatment 2 days after infection was less effective and the mortality rate reached 44%, although still being significantly lower (p < 0.01) than in untreated controls. A combined treatment with ACL and PA on the day of HSV-1 infection protected 93% of animals against the development of clinically detectable herpesvirus encephalitis.

The mechanism of poly I:C-induced antiviral activity in peritoneal macrophage

Macrophages play an important role in defense against virus infection by intrinsic resistance and by extrinsic resistance. Since interferon-induced enzymes which are 2'-5' oligoadenylate synthetase and P1/eIF-2 protein kinase have been shown to be involved in the inhibition of viral replication, I examined the mechanism by which poly I:C, an interferon inducer, exerts its antiviral effects in inflammatory macrophages infected with herpes simplex virus type 1 (HSV-1). The data presented here demonstrate that poly I:C-induced antiviral activity is partially due to the activation of 2'-5' oligoadenylate synthetase. The activation of 2'-5' oligoadenylate A synthetase by poly I:C is also at least partly mediated via the production of interferon-beta. Taken together, these data indicate that interferon-beta produced in response to poly I:C acts in an autocrine manner to activate the 2'-5' oligoadenylate synthetase and to induce resistance to HSV-1.

Administration of inactivated and detergent-treated influenza virus to mice before virus challenge reduces mortality

Formalin-inactivated virus (FIV) and the detergent-treated virus (DTV) preparations were tested for their ability to enhance the resistance of mice to experimental influenza infection. FIV (100 micrograms) was administered intravenously to mice. After 24 hr, animals were challenged with 5 LD50 dose intranasally. FIV-treated and non-treated (control) mice had 10% and 100% mortality, respectively. Similar results were obtained with the DTV (40 micrograms) preparation. The pulmonary virus titer of FIV-treated mice was lower when compared with the control. Mechanisms other than acquired immunity may have conferred the early resistance to virus infection in mice.

Poly I:C-induced antiviral and cytotoxic activities are mediated by different mechanisms

Macrophages play an important role in host defenses against tumors and virus infections by killing tumor or virus infected cells (extrinsic cytotoxicity) and by limiting virus replication within themselves (intrinsic antiviral activity). Since common macrophage products may be involved in both extrinsic cytotoxicity and intrinsic antiviral activity, we decided to investigate the mechanisms by which Poly I:C-activated macrophages resist infection with HSV-1 and inhibit the growth of tumor cells. The ability of macrophages to resist infection with HSV-1 or to inhibit growth of tumor cells was assessed following treatment with Poly I:C in the presence of antibodies to various cytokines or in the presence of inhibitors/scavengers of toxic macrophage products. Only antibodies to IFN-beta were able to abrogate the protective effects of Poly I:C in macrophages infected with HSV-1, suggesting that the antiviral activity induced by this immunomodulator was mediated by the production of IFN-beta, which acted in an autocrine manner. In contrast, anti-TNF-alpha, anti-IFN-alpha/beta anti-IFN-beta antibodies and inhibitors of nitric oxide and C1q production were all able to partially abrogate Poly I:C-induced cytostatic activity, suggesting that multiple mechanisms are involved in macrophage cytostasis. Our results indicate the Poly I:C-induced intrinsic antiviral and extrinsic cytotoxic activities are mediated by different mechanisms.

Colonization of adrenal glands and ovaries of mice by HSV-2 variants. I. Virological studies

HSV-2 strain ER was shown to consist of variants with different pathogenic phenotype: Variant ER+ replicates to high titers in the adrenal glands and the ovaries but much less in the spleen; the testes were not colonized. ER+ migrates to the spinal ganglia and is highly neuroinvasive after i.p. inoculation. Variant ER- replicates 100-1,000 fold less in the adrenal glands and the ovaries, but proceeds to the spinal ganglia without invading the CNS. However, both variants are highly neuropathogenic after direct i.c. injection. We conclude that neuropathogenicity, neuroinvasiveness and the ability to replicate in the adrenal glands as well as ovaries are each determined by different sets of genes. Replication in mouse embryo fibroblasts--but not in Vero and adreno cortical carcinoma Y1 cells--is different for both strains. Also the adsorption capacity to cultured cells differs as shown by addition of D.S. 500. ER- is eliminated from the blood stream more quickly than ER+. Finally, C. parvum reduces the rate of replication of both variants in the adrenal and the ovaries. It is concluded that different adsorption and replications rates of variants ER+ and ER- in cell types critical for spread of HSV are responsible for the different pathobiological properties.

Escherichia coli-derived envelope protein gD but not gC antigens of herpes simplex virus protect mice against a lethal challenge with HSV-1 and HSV-2

Immunization studies with HSV-1 and HSV-2 envelope proteins expressed in Escherichia coli were performed. After active immunization of mice with a gD-1 antigen (Leu53-Ala312) expressed as a fusion protein, the animals were protected from a lethal challenge with HSV-1 and HSV-2. In addition, antisera from rabbits immunized with the same gD-1 antigen also conferred passive immunity to mice against a challenge infection with either HSV-1 or HSV-2. In contrast to these successful gD-1 protection experiments, various gC-1 and gC-2 fusion proteins from E. coli failed to induce protective immunity. Moreover, the mice sera from immunized animals were not able to react with the authentic, glycosylated gC-1 and gC-2 envelope proteins, whereas sera raised against authentic gC-1 and gC-2 glycoproteins do recognize the gC fusion proteins from E. coli. These results indicate, that E. coli might represent an ideal system for expressing gD antigens as a possible component of a HSV vaccine, whereas gC antigen cannot be produced in an immunocompetent form in E. coli.

Role of interferon, antibodies and macrophages in the protective effect of Corynebacterium parvum on encephalomyocarditis virus-induced disease in mice

Treatment of mice with Corynebacterium parvum enhances their resistance to encephalomyocarditis (EMC) virus infection. In EMC-virus-infected mice, pretreated with C. parvum, neither interferon production nor antibody responses were increased. A decrease of virus recovery was observed in cultures of macrophages taken from the peritoneum of mice early after injection of C. parvum and infected with EMC-virus in vitro. The data suggest that C. parvum acts by increasing intrinsic antiviral activity of macrophages.

Mode of protection of mice against herpes simplex virus type 2 infection by Propionibacterium

We compared various strains of Propionibacterium with regard to protection of young adult mice against lethal infection with herpes simplex virus type 2 (HSV-2). Propionibacterium acnes, P. granulosum, and P. avidum were protective, while P. acidi-propionici and P. lymphophilum were ineffective. The protective effect proved to be in the cell wall fraction. Attempts were made to elucidate possible mechanisms of the protection using both effective and ineffective strains. The results strongly suggest that induction of interferon rather than activation of macrophages and natural killer cells by Propionibacterium pretreatment plays a crucial role, directly or indirectly, in protection against infection by herpes simplex virus. Propionibacterium only moderately protected newborn mice against HSV-2 infection.

Protection of mice against influenza virus infection: enhancement of nonspecific cellular responses by Corynebacterium parvum

Groups of C57BL/6J, BALB/c, BALB/c, nu+/nu+ mice, inoculated intranasally with Corynebacterium parvum (350 micrograms/mouse) were protected from death by an otherwise lethal dose of influenza virus, A/WSN (H1N1) inoculated 3 days later. The lungs of C. parvum-treated, virus-infected C57BL/6J, BALB/c, or BALB/c nu+/nu+ mice contained significantly less infectious virus than did controls, and this reduction was apparent as soon as 24 hr after virus inoculation. The maximum protective effect correlated with increased lung interferon levels. C. parvum treatment caused an increase in the lung cell number which was in part due to a large increase (ca. 10-fold) in macrophage content, and the natural killer cell activity was also enhanced, though not as markedly as occurred 3 days after infection. Most (greater than 85%) of the resident macrophages in normal lungs were susceptible to infection by virus (as indicated by hemadsorption), whereas most of those recovered from the lungs of C. parvum-treated mice resisted infection. Despite the increase in macrophage content, the level of specific immune responses to infection, such as cytotoxic T-cell activity, DTH reaction, and antihemagglutinin antibody, remained unchanged by C. parvum treatment so that the major if not only effect of this treatment was on the level of the less-specific components of the immune system.

Enhancement of natural resistance to influenza virus in lipopolysaccharide-responsive and -nonresponsive mice by Propionibacterium acnes

Lipopolysaccharide-responsive C3H/HeN mice were rendered resistant to a mouse-adapted strain of influenza (Aichi, H(3)N(2)) virus when Propionibacterium acnes was given either intranasally or intraperitoneally several days before virus infection. The time of P. acnes treatment was important since no protection was demonstrated when this agent was given either on the same day as or several days after virus challenge. In contrast, lipopolysaccharide-nonresponsive C3H/HeJ mice were not protected when P. acnes was administered intranasally at any time before infection; however, protection was demonstrated when P. acnes was given by the intraperitoneal route. Depending on the route of inoculation, P. acnes induced several distinctive immunological responses in the lungs of both C3H/HeN and C3H/HeJ mice. Intranasal inoculation was more effective in activating pulmonary macrophages in C3H/HeN than in C3H/HeJ mice. In contrast, intraperitoneal inoculation activated pulmonary natural killer cells in both mouse lines but did not activate pulmonary macrophages.

Early interactions of herpes simplex virus with mouse peritoneal macrophages

Adsorption of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) to resident peritoneal macrophages (PM) of 4-week-old Swiss albino (SA) and GR/AFib mice was studied. A significantly (P less than 0.05) higher HSV-2 adsorption rate was found with PM of SA mice than with PM of GR/AFib mice. Of added HSV-2 65% bound to the cells of SA mice over a 120-min period versus 15% to PM of GR/AFib mice. Only 15 to 20% of added HSV-1 bound to PM regardless of the mouse strain. These patterns of adsorption were found with all four HSV-1 and four HSV-2 strains tested. Pretreatment of PM with an HSV-2 mutant blocked the adsorption of added HSV-2. Thus, the receptors for HSV attachment seemed to be virus type selective. To avoid masking of adsorption by phagocytotic activity, the adsorption studies had to be performed at 4 degrees C. Transport of attached HSV-1 and HSV-2 to the nuclei of SA PM was studied with purified virus labeled with 32Pi and [3H]thymidine. In double-isotope experiments, only transport of HSV-2 was detected. The possible importance of differences in density or avidity of virus-binding receptors on the plasma membrane of PM is discussed in relation to macrophage-dependent focal liver necrosis, which was only demonstrable after intraperitoneal inoculation of HSV-2, not HSV-1, only in SA, not GR/AFib, mice.

Protectivity of herpes simplex virus antigens: studies in mice on the adjuvant effect of PICLC and on the dependence of protection on T cell competence

The efficacy of a herpes simplex virus type 1 (HSV-1) envelope antigen (EAG) preparation against HSV infection was studied in T cell competent and T cell deficient mice. Immuno-competent mice were successfully protected against herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) infection when immunized 2 weeks prior to this infection with a heat-inactivated whole virus preparation or a HSV-1 envelope antigen (HSV-1 EAG) preparation. Since HSV-1 EAG was considerably less effective than the whole virus preparation, a poly.riboinosinic-poly.ribocytidylic acid complex with poly-L-lysine and carboxymethylcellulose (PICLC) was used as adjuvant. Immunization with HSV-1 EAG plus PICLC resulted in a pronounced increase of this protection rate as compared with that obtained after immunization solely with HSV-1 EAG. PICLC alone, however, offered no protection when given 2 weeks before challenge. In T cell deficient nu/nu mice no protection was achieved with HSV-1 EAG while their T cell competent, heterozygous littermates were protected. From these results it may be concluded that T cell competence is a prerequisite for establishing a protective immunity against HSV infection after immunization with HSV-1 EAG.

Protection of mice against mouse hepatitis virus by Corynebacterium parvum

C57BL/6 mice that are highly susceptible to infection with mouse hepatitis virus type 3 were protected against intraperitoneal viral infection by simultaneous intraperitoneal injection of Corynebacterium parvum. No protection was observed when C. parvum was given intravenously or when it was injected intraperitoneally 3 days before viral infection. Protective effects were, however, consistently found when C. parvum was given 2 h before or 2 h after viral infection. Activity was seen only against 10 50% lethal doses and not against 100 50% lethal doses. C. parvum also caused a significant decrease of virus type 3. These data suggest a direct effect of C. parvum on virus-susceptible cells. Injection of C. parvum in mice caused activation of natural killer (NK) cells and of interferon production. However, these two effects were equally demonstrable at high and low doses of C. parvum, whereas protection against mouse hepatitis virus type 3 was not demonstrable at low doses of C. parvum. Thus, antiviral protection may be dissociated from activation of NK cells and induction of interferon.

Effect of Corynebacterium granulosum immunopotentiation on the pathogenesis of herpes simplex virus type 2 in BALB/c mice

Treatment of 4- to 6-week-old, 18- to 22-g male BALB/c mice with 0.6 mg of Corynebacterium granulosum resulted in a significant decrease in mortality due to challenge with herpes simplex virus type 2 (HSV-2). Optimal protection occurred when C. granulosum was injected 1 week before HSV-2 infection. C. granulosum-induced resistance to HSV-2 lasted up to 4.5 weeks. Studies involving immune spleen cell transfer and treatment with antilymphocyte serum demonstrated the importance of cell-mediated immunity in HSV-2 infection. However, C. granulosum protection was not transferable with spleen cells from C. granulosum-treated animals nor was C. granulosum treatment capable of completely overcoming the increased mortality which resulted from antilymphocyte serum treatment of HSV-2 infected mice. Under our experimental conditions, silica did not affect the mortality in BALB/c mice due to HSV-2 but significantly reduced the protective effects induced by C. granulosum. Attempts to transfer protection of HSV-2 challenge in suckling mice by using either glass-adherent or mixed peritoneal cells from either HSV-2-immunized or C. granulosum-treated animals were unsuccessful.

Macrophage dependence of polyriboinosinic acid-polyribocytidylic acid-induced resistance to herpes simplex virus infection in mice

The relative contributions of macrophages and lymphocytes to the induction of resistance to primary herpes simplex virus type 1 (HSV-1) infection by polyriboinosinic-polyribocytidylic acid complex [poly (I:C)] were investigated in C58 mice. The induction of resistance was found to be strongly dependent on macrophages compared to lymphocytes. Macrophage-deficient (silica-treated) mice produced less interferon and were not as responsive to prophylactic treatment of HSV-1 infections with poly (I:C) as were either normal, lymphocyte-deficient (cyclophosphamide-treated), or T-lymphocyte-deficient (anti-thymocyte serum-treated, adult-thymectomized) mice. Silica and cyclophosphamide treatments reduced the therapeutic activity of poly (I:C), whereas T-cell depletion did not have a significant effect. Similarly, the protection of mice with exogenous interferon was markedly reduced in silica-treated mice and moderately reduced in cyclophosphamide-treated mice, but unaffected in T-cell-deficient mice. Furthermore, suppression of HSV-1 plaque formation was obtained by cocultivation of infected mouse fibroblast monolayers with peritoneal (macrophage-rich) cells, but not with splenic (lymphocyte-rich) cells, from poly (I:C)-treated mice. Peritoneal cells did not protect heterologous (human) fibroblasts, suggesting that the protection of mouse embryo fibroblasts is mediated by interferon. Collectively, the data indicate that macrophages are required for the production of poly (I:C)-induced interferon and that macrophages and perhaps B-lymphocytes are important for mediating the protection against HSV-1 infection after interferon has been produced.

Clinical uses of microorganisms and their products

Although antibiotics and conventional vaccines are the two most familiar examples of man's exploitation of microorganisms as clinical allies, microorganisms and their products are assuming an increasingly prominent role in the diagnosis, treatment and prevention of human diseases. This report attempts to give a brief overview of the status of the use of microorganisms in clinical medicine and to identify potentially fertile areas for future progress in their clinical application, concentrating on areas other than the already extensively reviewed ones of antibiotics and classic immunization.

Effect of pyran on latency after herpes simplex virus infections

The immunomodulator pyran protected mice against both herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infections. In infections of the lip with HSV-1, prophylactic administration of pyran reduced the severity of the herpetic lesions and enhanced their resolution, but did not decrease the high incidence of development of latent HSV-1 infection of the trigeminal ganglia. In vaginal infections with HSV-2, prophylactic administration of pyran either systemically or locally reduced mortality, reduced the incidence of mice with vaginal HSV-2 infection, and did not alter the low incidence of latent infection of the spinal dorsal root ganglia. Pyran treatment before systemic herpetic infection after intravenous inoculation of HSV-2 also reduced mortality and virus replication, as evidenced by a decreased antibody response in the survivors, and it either reduced latent infection in the spinal dorsal root ganglia or did not predispose mice to latent infection. Treatment with the immunomodulator appeared to inhibit or reduce HSV infection early in viral pathogenesis in all three model systems, producing protection from clinical disease and resulting in less virus to induce a systemic antibody response, with either a reduction in latent virus infection or no enhancement of development of latency. In all of the HSV models, the development of latent herpetic infection was closely correlated with sufficient virus replication early in the infection to induce a systemic neutralizing-antibody response.

Interferon production and lymphocyte stimulation in human leucocyte cultures stimulated by Corynebacterium parvum

Killed C. parvum organisms stimulated a lymphoproliferative response in human peripheral leucocyte cultures of both adult and cord blood origin. They also induced high titres of interferon in cultures of adult leucocytes, but there was no correlation between the degree of lymphocyte stimulation and of interferon production. A considerable variability between donors was seen in both assays. The amount of interferon produced in C. parvum-stimulated cultures was considerably higher than that stimulated by the T-cell mitogens PHA and Con A and that induced by LPS. The anti-viral protein induced by C. parvum fulfilled the criteria of interferon and appeared to represent type II interferon.

Enhanced resistance against Junin virus infection induced by Corynebacterium parvum

The effects of intraperitoneal administration of Corynebacterium parvum on the course of Junin virus infection in mice were investigated. This treatment produced enhanced resistance to the virus infection, evidenced by an increase in both survival times and the proportion of survivors. The protective effect was dependent upon the dose of C. parvum, and 280 mug/g of body weight was found to be the optimal dose. In various experiments, about 80% of the infected animals receiving this dose survived, whereas survival ranged between 0 and 20% among untreated infected mice. Maximal protection was afforded by C. parvum when administered simultaneously with the virus. A smaller but significant degree of resistance was induced by C. parvum given 3 or 6 days after infection. C. parvum injected before infection was ineffective. Viral titers measured in the brains of C. parvum-treated and untreated mice at various times after infection were found to be comparable. In addition, there were no significant differences between circulating-antibody titers measured either by neutralization tests or by complement fixation. Depression of the reticuloendothelial system by treatment with silica particles also resulted in enhanced resistance to Junin virus infection, suggesting that the protective effect of C. parvum is not likely to be due merely to its capacity to stimulate macrophages. The present data, highlighting that the presence of high titers of Junin virus and disease do not necessarily correlated, suggest that in mice this disease is not the consequence of cell damage caused directly by the virus but of a still undefined indirect mechanism induced by the virus, not necessarily mediated by macrophages.

Enhanced resistance against encephalomyocarditis virus infection in mice, induced by a nonviable Mycobacterium tuberculosis oil-droplet vaccine

Female C57B1/10 mice injected intravenously (i.v.) with nonviable Mycobacterium tuberculosis Jamaica cells associated with oil-droplet emulsions (WCV) were highly resistant to the i.v. injection of encephalomyocarditis virus (EMCV). Resistance to infection (87% survival) was detected from 1 week to at least 12 weeks after injection of WCV. Mice vaccinated i.v. also were resistant to intraperitoneal, subcutaneous, or intramuscular virus challenge, but were not resistant to intracranial challenge. Mice vaccinated intraperitoneally also were resistant to virus infection, whereas WCV administered intramuscularly or subcutaneously did not protect mice from virus injected by any route. Less than 50% of WCV mice that survived virus challenge possessed serum anti-EMCV-neutralizing antibody (less than 1:10), and none had detectable (less than 1:10) serum interferon. Interferon was not detected in sera of WCV mice from 4 to 144 h after i.v. injection of EMCV. Studies concerning the effects of WCV on EMCV infection suggest that mice may be protected by mechanisms that inhibit early viral replication and spread of virus to the central nervous system.