R. Jennings

A genetically inactivated herpes simplex virus type 2 (HSV-2) vaccine provides effective protection against primary and recurrent HSV-2 disease

Abstract A glycoprotein H (gH)-deleted herpes simplex virus type 2 (HSV-2) was evaluated as a vaccine for the prevention of HSV-induced disease. This virus, which we term a DISC (disabled infectious single cycle) virus, can only complete one replication cycle in normal cells and should thus be safe yet still able to stimulate broad humoral and cell-mediated antiviral immune responses. A gH-deleted HSV-2 virus that has been tested as a vaccine in the guinea pig model of recurrent HSV-2 infection was constructed. Animals vaccinated with DISC HSV-2 showed complete protection against primary HSV-2–induced disease, even when challenged 6 months after vaccination. In addition, the animals were almost completely protected against recurrent disease. Even at low vaccination doses, there was a high degree of protection against primary disease. A reduction in recurrent disease symptoms was also observed following therapeutic vaccination of animals already infected with wild type HSV-2.

Clinical studies of monovalent inactivated whole virus and subunit A/USSR/77 (H1N1) vaccine: serological responses and clinical reactions

The clinical acceptability and antibody responses to graded doses of whole virus, aqueous surface antigen and adsorbed surface antigen influenza A/USSR/92/77 (H1N1) virus vaccines were assessed in 1335 healthy volunteers in a double-blind, multi-centre study conducted in the U.K. in February and March 1978. Before vaccination the presence of haemagglutination-inhibiting (HI) and neuraminidase-inhibiting (NI) serum anti-bodies to the vaccine virus was infrequent and in low titres in volunteers aged ≤ 25 years but was more frequent in older persons. In volunteers aged ≤ 25 years, who were sero-negative for HI antibody before vaccination, the HI antibody responses following one dose of vaccine were generally of low frequency and titre for all doses and types of vaccine. Nevertheless, whole virus or subunit vaccines with high antigenic content (≥ 47 μg haemagglutinin (HA) per dose) induced HI antibody responses in at least 60% of recipients. Following two doses of whole virus, aqueous or adsorbed surface antigen vaccine containing at least 9 μg HA per dose, serum HI titres of ≥ 40 were detected in 69–100% of recipients. In volunteers aged ≥ 26 years, who received a single dose of any of the test vaccines containing at least 3 μg HA, the HI antibody responses were frequent and post vaccine titres of ≥ 40 were detected in 80% of vaccinees. A ‘shallow’ dose response effect over a wide range of antigen concentrations of whole virus (5–94 μg HA per dose) or subunit vaccines was noted for each age group. Both the geometric mean HI antibody titres and proportion of vaccinees developing HI titres ≥ 40 were similar for each age group when comparable doses of vaccine were given by the subcutaneous and intradermal routes. A preliminary study of the NI antibody responses to vaccination indicated that all the whole virus and subunit vaccines stimulated serum NI antibodies in a proportion of recipients. All vaccines were clinically well tolerated.

Induction of a protective immune response by mucosal vaccination with a DISC HSV-1 vaccine

The vaccine potential of a genetically disabled Herpes Simplex Virus Type 1 virus (DISC HSV-1) was investigated in the guinea pig model of intravaginal (i.vag.) HSV-2 infection. Three mucosal vaccination routes, i.vag., intranasal (i.n.) and oral, were compared for their ability to protect guinea pigs from challenge with wild-type HSV-2. Each was effective, particularly the i.n. route, which almost completely abolished primary disease. This was accompanied by significantly lower challenge virus titres in vaginal swabs collected from the vaccinated animals. In all cases, vaccination with the inactivated virus preparation provided substantially less protection from disease than the live DISC HSV-1 by the equivalent route. Antibody levels in serum and vaginal washes were measured both after vaccination and challenge by ELISA and neutralization tests. The highest titres were observed following administration of the DISC HSV-1 vaccine by the i.n. route. Significant increases in IgA and IgG in vaginal wash fluids were also found in these vaccinated animals.

Immunopotentiation of local and systemic humoral immune responses by ISCOMs, liposomes and FCA: role in protection against influenza A in mice

The immunogenicity and protective efficacy of an influenza A subunit vaccine preparation administered to mice in an aqueous form, or presented as immunostimulatory complexes (ISCOMs), liposomes or with Freunds complete adjuvant (FCA), were assessed in comparative studies with live infectious virus. Both intranasal and parenteral routes of administration were assessed. An enzyme-linked immunosorbent assay (ELISA) was used to measure nasal wash and serum antibody responses in groups of unprimed mice, while protection was determined by the recovery of homologous influenza virus from mouse nasal washes and lung homogenates following challenge infection by the intranasal route. The results showed that parenteral administration of the influenza antigen preparations induced variable levels of both local and systemic antibodies at weeks 3, 7 and 22 postimmunization. Although the overall greatest levels of antibody and protection were elicited in mice following live virus infection, formulation of influenza surface haemagglutinin (HA) and neuraminidase (NA) proteins into ISCOMs elicited high and persistent antibody responses and provided relatively good protection of the upper and lower respiratory tracts of these animals. The results also show a relatively poor effect of the subunit antigen preparations in promoting humoral immune responses and protection irrespective of the nature of their presentation, when given by the intranasal route.

Immunity to influenza in ferrets

The response of ferrets to inoculation with tri-(n-butyl) phosphate split influenza A/Aichi/68 virus vaccine is reported. Normal ferrets did not produce detectable levels of serum HI antibody following inoculation with a single dose of either 640 or 6400 CCA of virus vaccine but produced low titres of antibody following two inoculations of 6400 CCA of virus. This antibody was insufficient to protect the animals against challenge infection with influenza virus A/Hong Kong/68. Ferrets which had been primed by previous infection with heterotypic influenza virus A/PR/8/34, however, responded to immunization with a single dose of 640 CCA of TNBP-split A/Aichi/68 virus by the production of low titres of serum HI antibody. Following immunization these animals were found to be susceptible to challenge infection. The difference in immunogenicity between the TNBP-split vaccine and similar concentrations of whole virus vaccine given to primed ferrets is discussed.

The IgA and subclass IgG responses and protection in mice immunised with influenza antigens administered as ISCOMS, with FCA, ALH or as infectious virus

SummaryComparative studies on the local IgA, and circulating IgG subclass antibody responses of mice to A/Sichuan/2/87 (H3N2) influenza virus surface antigens administered with different carrier or delivery systems by the parenteral route, were carried out. The results obtained were compared with the responses observed following live influenza virus infection, and the protection afforded to these animals by these various preparations determined.Infection with live virus elicited early and high levels of protection against homologous virus challenge and this correlated with both local IgA and circulating IgG2a antibody levels. When incorporated into immunostimulating complexes (ISCOMS), A/Sichuan surface antigens promoted high levels of local IgA and circulating IgG1 antibody, and achieved a more rapid and more solid immunity against homologous virus challenge infection, than that elicited by the same surface antigens administered alone or together with Freunds complete adjuvant or alhydrogel.

Antibody Responses and Protection in Mice Immunized with Herpes Simplex Virus Type 1 Antigen Immune-stimulating Complex Preparations

The formation of immune-stimulating complexes (iscoms) obtained by mixing the glycoside Quil A with an antigen preparation derived from herpes simplex virus type 1 (HSV-1)-infected cell cultures using a zwitterionic detergent is described. The HSV-1 antigen preparation incorporated into iscoms elicited significantly greater antibody responses in mice than the same preparation administered together with aluminium hydroxide gel, and provided complete protection against HSV-1 or HSV-2 lethal, systemic challenge infection in animals given a single dose containing 5 micrograms of protein. The HSV-1 iscom preparation also provided significant protection in mice against local reactions following challenge with HSV-1 by skin scarification.

Raised Inflammatory Markers in Semen From Men With Asymptomatic Chlamydial Infection

The aim of this study was to determine whether interleukin (IL)-6 and IL-8 concentrations, as well as numbers of seminal leukocytes in a population of infertile men, some of whom were Chlamydia trachomatis positive, were related to chlamydial infection. Our patient group included 255 men attending for diagnostic semen analysis as part of infertility investigations. Significantly raised levels of IL-8, but not IL-6, were found in C trachomatis-infected patients but not in uninfected patients. Raised IL-8 levels in semen were also associated with an increase in semen volume. There was a relationship between C trachomatis infection and lower progressive motile sperm, as well as an increase in seminal leukocytes. The overall prevalence rate for C trachomatis was 6.2%, and more infections were detected in semen than in first void urine. This study supports the suggestion that IL-8 might be used as a marker for male genital tract infection, especially when due to C trachomatis. In this study, there was a relationship between the presence of C trachomatis in semen and alterations of some semen parameters. Further investigations should be performed to understand the disparities of first void urine and semen testing for detection of C trachomatis in males.

Vaccination prevents latent HSV1 infection of mouse brain

Herpes simplex encephalitis (HSE) is a rare but very serious disorder caused by herpes simplex type 1 virus (HSV-1). Treatment with acyclovir decreases mortality but many patients still suffer cognitive impairment subsequently. A vaccine against HSV1 would therefore be of great value. HSV-1 has been implicated also in Alzheimer’s disease (AD): we established that HSV1 resides in the brain of about two thirds of AD patients and aged normal people, and that in carriers of the type 4 allele of the apolipoprotein E gene, it is a strong risk factor for AD. Thus a vaccine against HSV-1 might prevent development of AD in some cases. To find whether a vaccine of mixed HSV-1 glycoproteins (ISCOMs), which protects mice from latent HSV-1 infection of sensory ganglia, prevents HSV1 latency in the CNS, ISCOM-vaccinated or unvaccinated animals were infected with HSV-1. Using polymerase chain reaction (PCR) we detected HSV-1 in brain from 16 of 39 unvaccinated mice (41%), but only 3 of 41 vaccinated mice (7%) (P 0.001). Thus, ISCOMs protect the CNS also, suggesting their possible future usage in humans.

Immune responses in mice induced by HSV-1 glycoproteins presented with ISCOMs or NISV delivery systems

The purpose of this study was to evaluate the immunogenicity of a herpes simplex virus type I (HSV-1) antigen preparation, obtained following zwitterionic detergent treatment of virus, and incorporation of the antigens into either immunostimulating complexes (ISCOMs) or non-ionic surfactant vesicles (NISV) delivery systems. Using Balb/c mice the ISCOM and NISV HSV-1 vaccines were assayed for their capacity to induce and enhance both the humoral and cellular immune responses, and to elicit protection against both homologous and heterologous virus challenge. The serum from animals vaccinated with either the NISV or the ISCOM HSV-1 antigen preparation, were found to contain high levels of total IgG and IgG1 and IgG2a subclass antibodies. In addition, both preparations were found to induce high neutralizing (NT) antibody levels following a two immunization protocol and to provide some protection against homologous and heterologous HSV challenge infection. Lymphoproliferative responses were observed in cultures of splenocytes from mice immunized with both HSV-1 NISV vaccine and HSV-1 ISCOMs vaccine, following various antigenic stimuli in vitro. In general, these were most marked in animals immunized with the HSV-1 NISV preparation, and particularly so when the splenocytes were stimulated in vitro with live HSV-1. Both the NISV and ISCOM HSV-1 vaccines were found to have induced interleukin 2, interleukin 10 and interferon-gamma in spleen cell culture supernatants, although again, the highest responses in general were observed in supernatant fluids from spleen cell cultures from animals immunized with the HSV-1 NISV preparation. These results suggest that a wide range of immune activity can be elicited by HSV-1 antigens presented to the immune system of mice in these formulations.