Treatment of experimental encephalomyelitis with a novel chimeric fusion protein of myelin basic protein and proteolipid protein

It has been shown that peripheral T cell tolerance can be induced by systemic antigen administration. We have been interested in using this phenomenon to develop antigen-specific immunotherapies for T cell-mediated autoimmune diseases. In patients with the demyelinating disease multiple sclerosis (MS), multiple potentially autoantigenic epitopes have been identified on the two major proteins of the myelin sheath, myelin basic protein (MBP) and proteolipid protein (PLP). To generate a tolerogenic protein for the therapy of patients with MS, we have produced a protein fusion between the 21.5-kD isoform of MBP (MBP21.5) and a genetically engineered form of PLP (deltaPLP4). In this report, we describe the effects of treatment with this agent (MP4) on clinical disease in a murine model of demyelinating disease, experimental autoimmune encephalomyelitis (EAE). Treatment of SJL/J mice with MP4 after induction of EAE either by active immunization or by adoptive transfer of activated T cells completely prevented subsequent clinical paralysis. Importantly, the administration of MP4 completely suppressed the development of EAE initiated by the cotransfer of both MBP- and PLP-activated T cells. Prevention of clinical disease after the intravenous injection of MP4 was paralleled by the formation of long-lived functional peptide-MHC complexes in vivo, as well as by a significant reduction in both MBP- and PLP-specific T cell proliferative responses. Mice treated with MP4 were resistant to disease when rechallenged with an encephalitogenic PLP peptide emulsified in CFA, indicating that MP4 administration had a prolonged effect in vivo. Administration of MP4 was also found to markedly ameliorate the course of established clinical disease. Finally, MP4 therapy was equally efficacious in mice defective in Fas expression. These results support the conclusion that MP4 protein is highly effective in suppressing disease caused by multiple neuroantigen epitopes in experimentally induced demyelinating disease.

Pertussis-specific cell-mediated immunity in infants after vaccination with a tricomponent acellular pertussis vaccine

The aim of this study was to investigate pertussis-specific cell-mediated immunity in infants vaccinated with a tricomponent acellular vaccine. Infants were investigated during a primary vaccination schedule from the third month of life to the sixth month as well as before and after a booster at 15 to 24 months. This is the first report of specific cell-mediated immune responses to pertussis-related antigens in infants below the age of 12 months. Our data show that the vaccine induces T-cell responses specific for the vaccine components, detoxified pertussis toxin, filamentous hemagglutinin, and pertactin, that increase progressively over the course of the vaccination schedule. In contrast to declining antibody titers, cell-mediated immune responses are stable over the postprimary to prebooster period. Vaccination results in a progressive increase in the number of T cells that express activation marker CD45RO preferentially on CD4-positive T cells after stimulation with pertussis antigens. Measurements of cytokine secretion profiles demonstrated a preferential induction of interleukin 2- and gamma interferon-producing T-helper 1 cells and only low production of interleukin 10. The observed persistence of the specific cell-mediated immunity may have a bearing on the protective mechanisms induced by pertussis vaccination. Cell-mediated immunity requires further study, particularly to improve our understanding of the persistence of protection afforded by vaccination up to the administration of booster doses.

Immunological response to the Brucella abortus GroEL homolog

Western blot (immunoblot) analysis of sera from cattle vaccinated with Brucella abortus S19 exhibit an elevated serologic response to Hsp62, the GroEL homolog (BaGroEL). Serologic screening of individual cows vaccinated with B. abortus S19 revealed no correlation between the immune response to BaGroEL and protection against a challenge with virulent organisms. The humoral immune response to BaGroEL was restricted to a region of the mature protein which mapped to amino acids 317 to 355 and may represent a useful diagnostic tool for monitoring exposure to B. abortus. Immunity to a challenge with virulent B. abortus S2308 was not observed in the BaGroEL vaccinated mouse model.

Staphylococcus aureus vaccination for dialysis patients--an update

Staphylococcus aureus infections are a major cause in both hemodialysis and peritoneal dialysis patients. The availability of a safe and effective protective vaccine would be of great benefit to these patients, but attempts at using vaccines consisting of inactivated whole cells have been unsuccessful. This article discusses an alternate approach to S. aureus vaccine design using a capsular polysaccharide conjugate and preliminary results in hemodialysis and peritoneal patients.

Virulence and vaccine potential of Salmonella typhimurium mutants deficient in the expression of the RpoS (sigma S) regulon

The alternative sigma factor RpoS (sigma S) is required for Salmonella virulence in mice. We report the immunizing capacity of Salmonella typhimurium rpoS and rpoS aroA mutants to protect susceptible BALB/c mice against subsequent oral challenge with virulent S. typhimurium. When administered orally or intraperitoneally, rpoS derivatives of the mouse-virulent S. typhimurium strains, C52 and SL1344, were highly attenuated and were efficient single-dose live vaccines. rpoS aroA mutants were more attenuated than corresponding single aroA or rpoS mutants, as assessed after oral or intraperitoneal administration, but retained significant ability to protect mice against salmonellosis. Salmonella rpoS and rpoS aroA mutants therefore deserve serious consideration for rational vaccine design. Consistent with this, Salmonella typhi Ty2, a 'wild-type' strain used widely for the development of human live-vaccine candidates against typhoid fever, was shown to be defective for rpoS. In addition, our results demonstrate that rpoS not only controls the growth and persistence of S. typhimurium in deep lymphoid organs, but also plays a role during the initial stages of oral infection.

Screening for sexually transmitted diseases in an HIV testing clinic; uptake and prevalence

OBJECTIVE

To estimate the prevalence of sexually transmitted diseases (STDs) and the acceptability of STD screening among people seeking an HIV antibody test in an established free standing HIV testing clinic.

DESIGN

A 9 month period prevalence study conducted between August 1993 and April 1994.

SETTING

The Same Day Testing Clinic (SDTC) for HIV antibodies at the Royal Free Hampstead NHS Trust Hospital, London.

SUBJECTS

242 males and 160 females attending the Same Day Testing Clinic.

OUTCOME MEASURES

The prevalence of STDs including gonorrhoea, chlamydia, syphilis and hepatitis B and the percentage of clinic attenders accepting an STD screen.

RESULTS

Of those invited to take part in the study 69% of the males (242/350) and 59% (160/269) of the females agreed to be screened although for a variety of reasons not everyone agreed to a full screen. Two cases of untreated syphilis, no cases of gonorrhoea and six cases of chlamydia were detected. Four people had active, previously undiagnosed herpes while three had genital warts. Evidence of previously unknown hepatitis B infection was found in 26 people. Despite a high level of previous contact with genitourinary medicine services, uptake of hepatitis B vaccination among those homosexual men eligible for immunisation was low (28%; 23/83). Nine (4%) of the males, but none of the females screened for STD were found to be HIV antibody positive.

CONCLUSION

Among people seeking an HIV antibody test in an established free standing HIV testing clinic, the prevalence of acute STDs was low. However, evidence of previously undiagnosed hepatitis B infection was found in a number of subjects and uptake of vaccination among those most at risk had been low. While opportunistic screening for STD was acceptable to almost two thirds of HIV testing clinic attenders, a substantial minority nonetheless declined this offer. Selective STD screening could be offered to those people seeking an HIV test who report never having been screened before, as both cases of positive syphilis serology and all those of chlamydia were in people who had not previously been screened. All those at risk for hepatitis B infection should be encouraged to establish their infection status and be immunised where appropriate.

Local and systemic antibody levels against protein D of Haemophilus influenzae following immunization and infection in rats

Outer membrane proteins of Haemophilus influenzae are considered as possible vaccine candidates against non-typable H. influenzae (NTHi), a major cause of respiratory infections. Here, we study local and systemic antibody responses to protein D, a well-conserved 42-kDa membrane protein, following local and systemic immunization, and experimental acute otitis media (AOM) with NTHi and H. influenzae type b (Hib) in rats. Animals that were challenged and rechallenged in the middle ear with Hib strain Minn A or NTHi strain 1161 developed IgG and IgA antibodies in serum but not in middle ear lavage (MEL) material or saliva. In contrast, following per oral immunization with NTHi strain 772 and Escherichia coli JM83 (pHIC348) (containing protein D gene) and, to a lesser degree after intranasal inoculation of NTHi strain 772, high saliva IgA antibodies to protein D developed, but there was no rise in antibodies to protein D in the MEL material or the sera of these animals. These results show that protein D can elicit different systemic and local antibody responses depending on the site of delivery and the form of administration. Furthermore, experimental AOM with NTHi and Hib induces systemic IgG and IgA antibodies to protein D but fails to induce a mucosal immune response.

Protection against lethal viral infection by vaccination with nonimmunodominant peptides

CTL response of H-2b mice to influenza PR8 virus is directed against the nucleoprotein (NP)-derived immunodominant 366-374 (NP366PR8) peptide presented by the Db molecule. However, NP has three nonimmunodominant peptides corresponding to the 17-25 (NP17), 55-63 (NP55), and 97-105 (NP97) sequences that have the Db consensus motifs and bind to the Db molecule with an intermediate (NP55) or low (NP17 and NP97) affinity. In a previous report, we have shown that NP55 peptide is naturally processed by infected cells. In the present work, we studied whether nonimmunodominant peptides can protect mice against viral infection. Antiviral protection was evaluated by measuring three parameters: survival after inoculation of a lethal dose of mouse-adapted PR8 virus, percentage of pulmonary lesions in surviving mice, and virus clearance from lungs of infected mice. Our results showed that immunization of B6 mice with nonimmunodominant peptides protected from PR8 virus infection, although less efficiently than immunization with the immunodominant NP366PR8 peptide. Protection was mediated by CD8 T cells. The efficacy of nonimmunodominant peptides correlated with their Db binding affinity; the low affinity binders NP17 and NP97 induced a weaker protection than the intermediate affinity binder NP55. A mixture of NP366PR8 and nonimmunodominant peptides gave a higher protection than NP366PR8 peptide alone. In conclusion, nonimmunodominant peptides protect against a viral infection with an efficacy that is proportional to their affinity for the restricting class I molecule.

Tetanus: a rare but preventable cause of mortality among drug users and the elderly

Forty deaths due to tetanus were reported in Lazio, Italy, during 1985-1994. Retired persons accounted for 48% of all deaths. Intravenous drug use was the most commonly identified risk factor among individuals aged less than 40 years. The frequent utilization of curative health services by drug users and the elderly should be used as an opportunity to update their immunization status.

Safety and immunogenicity of a combined hepatitis A and hepatitis B vaccine in young healthy adults

BACKGROUND

A combination of hepatitis A and hepatitis B monovalent vaccines could offer advantages for disease control programs in terms of convenience, compliance and cost.

METHODS

Under randomized, double-blind conditions, 156 healthy young adults were divided into 3 groups to receive 1 of 3 lots of a combined hepatitis A/hepatitis B vaccine administered at months 0, 1, and 6. Safety and immunogenicity were assessed after each dose.

RESULTS

Transient and predominantly mild reactions were reported by slightly more than half the vaccinees; no serious adverse effects were relate to vaccination. One month after dose 2, all subjects had converted to the hepatitis A component. Geometric mean titers (GMTs) of antibodies of hepatitis A virus varied from 4415 to 4882 mIU/ml in the three groups. For hepatitis B, most vaccinees (73%-92%) had protective levels of antibodies to hepatitis B virus (anti-HBs) after the second dose, and all were sero-protected after the booster. Anti-HBs GMTs at month 7 ranged from 1917 to 3298 mIU/ml.

CONCLUSIONS

No statistically significant differences were observed between vaccine lots. The combined hepatitis A/hepatitis B vaccine was safe and clinically well tolerated and induced immune responses quantitatively similar to those obtained with the respective monovalent vaccines.

Further search for small molecular inactivants capable of eliciting respiratory mucosal immunogenicity by modifying Sendai virus core RNA

Five groups of 32 chemicals were examined regarding their immunological functions as modifier inactivants to make inactivated Sendai nasal vaccine using a contact exposure experiment, direct immunofluorescent method, and serum HI titer. (1) Five of the nine reactive groups of reactive dyes (2-chloropyridine, 2, 4, 6-trichloropyrimidine, vinylsulfonic acid, epichlorohydrin and beta-chloroethylamine) induced complete or almost complete defense in the entire respiratory tract, and the four other vaccines brought about slight infection in the respiratory tracts. There was no marked rise in serum HI titers post-exposure, despite uneven development. (2) Of the four sizable substituted AS naphthol vaccines, naphthol AS-IRG and AS-G vaccines elicited nearly complete defense, but the two other vaccines, inactivated with more elongated molecules, invited rare and successive infections. The three immune groups produced invariably high serum HI titers. (3) Of the six naphthalene derivative vaccines, two (3-hydroxy-2-naphthoic acid methylester and 2-naphthol-6-sulfonic acid) induced complete or almost complete protection. But two vaccines brought about less protection, and the remaining two vaccines caused heavy infections. (4) Of the six benzene derivative vaccines, both m-nitrobenzenesulfonic acid and isatoic anhydride induced complete protection. Three vaccines permitted slight infections but 2, 4, 6-trinitrobenzenesulfonic acid vaccine caused severe infection. (5) Of the seven food dye vaccines, only orange I induced complete or nearly complete defense, while the other dye vaccines were inferior. In effect, twelve inactivated Sendai nasal vaccines modified the ribose and/or phosphate groups of the virus core RNA through five groups of small-sized molecules with specially fixed side chains, and elicited complete or almost complete respiratory mucosal defense. The viral stabilization requiring the least alteration of the configuration will be involved in the chemical modification.

Protection against lethal influenza virus encephalitis by intranasally primed CD8+ memory T cells

The neurotropic influenza virus strain A/WSN (H1N1) caused a rapidly fatal encephalitis after intracerebral inoculation into naive mice. Intranasal immunization with the same virus (homotypic) completely protected mice against a subsequent intracerebral challenge with A/WSN; there was no clinical disease, and infectious virus could not be recovered from the brain. In vivo depletion of CD4+ or CD8+ T cell subsets did not affect homotypic protection, and the pups of immune mothers were also protected against a lethal intracerebral challenge with A/WSN, suggesting that the Ab produced by intranasal priming was sufficient to protect mice against later intracerebral infection. Intranasal immunization with the heterotypic influenza strain A/X31 (H3N2) did not generate protective Ab, but despite an acute illness, 80% of mice survived the subsequent intracerebral challenge. Immune protection was associated with CD8+ T cell infiltration throughout the brain substance, together with widespread up-regulation of intracerebral MHC class I and MHC class II expression. In vivo T cell subset depletion showed that heterotypic protection was dependent upon CD8+, but not CD4+, T cells. This model system demonstrates some of the mechanisms through which the immunity generated by an initial extracerebral virus infection may protect against later intracerebral virus replication.

Recurrent hearing impairment and nystagmus induced by repeated antigen exposure in actively sensitized guinea pigs

Although many studies have suggested a relation between allergy and Ménière's disease, the pathophysiology of this condition remains controversial. The aim of this study was to clarify whether an anaphylactic reaction in the inner ear can disturb hearing and equilibrium, and whether such disturbances recur in response to repeated anaphylactic reactions. Increases in audiological threshold, nystagmus, and endolymphatic hydrops were observed in response to a single exposure to antigen administered to actively sensitized guinea pigs. The increase in audiological threshold was maximal 10 h after antigen challenge (p < 0.005) and returned to the baseline level after 7 days. Nystagmus and the increase in audiological threshold induced by antigen exposure were inhibited by prior administration of pemirolast potassium (p < 0.05), an inhibitor of chemical mediator release from mast cells. A second challenge with antigen 7 days after the first also induced an increase in audiological threshold (p < 0.05) and nystagmus. These results suggest that studies of repeated antigen challenge in actively sensitized animal models may increase our understanding of the pathophysiology of Ménière's disease.

[Preventive health in childhood]

A study evaluating use, compliance and activities of a child health care program at a health center in Granada. The data, taken over a period of five years, showed that 75.2% of one month old infants and 94% of three month old infants used the program. The three month old group showed the highest rate of compliance, where as the group of two year old infants had the lowest. Clinical visits demonstrated a high level of use, between 84-100%. Data about lactating mothers and vaccinations showed a low number of patients recorded, which is similar to the data published in other journals.

Comparison of IL-2- and IL-4-transfected B16-F10 cells with a novel oil-microemulsion adjuvant for B16-F10 whole cell tumour vaccine

The use of whole cell tumour vaccines in the treatment of malignant melanoma has given mixed results. Cytokine-transfected tumour cells as vaccine have shown efficacy in animal models but need to be compared with other means of enhancing a systemic anti-tumour immune response. A new generation of immunological adjuvants claimed to be more effective than the conventional adjuvants is now available for assessment. We have investigated the action of an oil-microemulsion adjuvant formulation (IDEC antigen formulation (IDEC-AF)) in the B16-F10 murine melanoma model. After standardisation of the whole cell tumour vaccination protocol we showed that mice vaccinated with whole irradiated cells combined with IDEC-AF produced a significant inhibition of tumour growth, following a challenge with live tumour cells, when compared with mice vaccinated with whole cell vaccine alone. IDEC-AF was superior to two conventional adjuvants, namely alum and incomplete Freund's adjuvant and a more reliable response was achieved with the oil-microemulsion adjuvant compared with IL-2-transfected cells. In addition, the adjuvant was comparable in efficacy to IL-4-transfected B16-F10 cells. Given the practical difficulty in using cytokine-transfected tumour cells and the limited therapeutic range of some cytokines, a cheap and easy to deliver adjuvant formulation proved equally or more effective than some of the currently clinically used transfected cytokines.

In vivo effects of monoclonal antibody against ICAM-1 and LFA-1 on antigen-induced nasal symptoms and eosinophilia in sensitized rats

We applied anti-ICAM-1 and anti-LFA-1 monoclonal antibody (mAb) to ovalbumin-sensitized rats and examined the effects on nasal eosinophilia and nasal symptoms following topical antigen challenge. In a general and local immunization (GLI) group of rats, the mAbs were applied during the booster topical immunization period. In a general immunization group and a local immunization (LI) group of rats, the mAbs were applied during the immunization period. The number of sneezes and nasal scratching movements occurring soon after topical antigen (Ag) challenge was significantly suppressed in the GLI and LI group rats. Eosinophil infiltration into nasal mucosa 24 h after Ag challenge was also significantly suppressed in GLI and LI group rats. These findings suggest that the ICAM-1/LFA-1 system is important in topical allergic inflammation in rats.

Vaccination with herpes simplex virus type 1 glycoprotein K impairs clearance of virus from the trigeminal ganglia resulting in chronic infection

Following primary ocular infection, HSV-1 establishes a latent infection in the trigeminal ganglia with the complete absence of detectable infectious virus. Recently, we showed that vaccination of BALB/cJ with HSV-1 glycoprotein K (gK), but not other HSV-1 glycoproteins, significantly exacerbated the severity of HSV-1-induced ocular disease and herpetic dermatitis (H. Ghiasi et al. J. Virol. 68, 2347-2354, 1994). We now report that prior vaccination with gK blocked viral clearance from trigeminal ganglia until at least Day 56 postinfection, resulting in a chronic infection. The significance of this novel finding with respect to potential harmful complications associated with the immune response to gK is discussed.

Sensitization and reactogenicity of two doses of candidate antileprosy vaccine Mycobacterium w

M.w vaccine is one of the antileprosy vaccines under test in an ongoing comparative vaccine trial in South India. The objective of the present study was to examine the sensitizing ability, as measured by skin test reactions to Rees' MLSA and lepromin, and reactogenicity of M.w vaccine in the local population. Two doses of M.w, 1 x 10(9) bacilli and 5 x 10(9) bacilli, were used, in two separate studies of 395 and 400 "healthy" individuals aged 1-65 years. In each study, the study subjects received either M.w vaccine or normal saline (control), by random allocation. The results showed that healing of vaccination lesions was uneventful although the healing process was somewhat prolonged with the higher dose. The mean size of lesions was 7.0 mm and 9.5 mm with the low and high doses of the vaccine, respectively. The results also showed that M.w vaccine in a dose of 1 x 10(9) bacilli, failed to induce post-vaccination sensitization as measured by reactions to Rees' MLSA and by Fernandez and Mitsuda reactions to lepromin-A. However, when the dose of the vaccine was increased to 5 x 10(9) bacilli the mean sizes of post-vaccination reactions to Rees' MLSA and lepromin-A (both early and late) were significantly larger in the vaccine group compared to that in the control group. The sensitizing effect attributable to the vaccine was of the order of 1.5 mm to 1.8 mm.

Characterization of the protective borreliacidal antibody response in humans and hamsters after vaccination with a Borrelia burgdorferi outer surface protein A vaccine

Significant borreliacidal antibody was induced in volunteers and hamsters 60 days after primary and secondary vaccination with high concentrations of recombinant outer surface protein A (rOspA). However, the borreliacidal antibody response waned rapidly. Only 1 person had detectable cidal activity 180 days after vaccination. Similarly, the borreliacidal antibody response waned rapidly in hamsters by week 10 of vaccination. By contrast, the total anti-rOspA antibody response remained elevated in volunteers and hamsters. When isolates of Borrelia burgdorferi sensu lato were incubated in sera from vaccinated humans or hamsters, only the vaccine-specific isolate was killed. These results were confirmed by challenging rOspA-vaccinated hamsters with different isolates of B. burgdorferi sensu lato. The results showed that monitoring total rOspA antibody is inappropriate for evaluating the efficacy of an rOspA vaccine. The rOspA vaccine must be improved to yield comprehensive protection and maintain sustained levels of protective borreliacidal antibodies.

Risk factor for neonatal tetanus in west Burkina Faso: a case control study

A case-control study was carried out to identify risk factors for neonatal tetanus in rural Burkina Faso. Each of the 31 cases identified prospectively were matched with two controls. Risk factors such as the instrument used to cut the umbilical cord and the qualification of the midwives were only identified in the univariate analysis. The multifactorial analysis identified factors commonly believed to be associated with neonatal tetanus: lack of mother's immunization and place of birth other than maternity clinics. However, applying karite nut butter on the umbilical cord was found to be a strong independent factor associated with neonatal tetanus. Immunization of mothers against tetanus should be enforced. Health education must take into consideration sociocultural realities of these populations.

Common (but not always considered) viral infections of the lower respiratory tract

Viral lower respiratory tract infections continue to cause a great deal of morbidity and mortality in the United States and worldwide, despite advances in treatment options, chemoprophylaxis, and vaccine development. The availability of ribavirin has improved the outlook in high-risk patients who develop respiratory syncytial virus bronchiolitis while intensive efforts are continued to develop an efficacious and safe vaccine. Respiratory syncytial virus immunoglobulin may prove to be a useful tool in the armamentarium of the pediatrician to prevent or modify respiratory syncytial virus disease in individual patients. Influenza vaccination and chemoprophylaxis remain mainstays in the prevention of influenza disease in high-risk individuals. The availability of a vaccine for varicella and a wider dissemination of measles vaccine, particularly in developing nations, may well limit the adverse outcomes associated with pneumonias caused by these two viruses. The transplant patient and other immunocompromised patients will continue to challenge clinicians and scientists to provide innovative and effective therapies for viral infections. The exciting advances in clinical and research virology over the last decade offer much hope to practicing pediatricians who struggle with offering prevention strategies and treatment options for their patients. Viral lower respiratory tract infections will never be eliminated as a clinical problem, although the morbidity and mortality associated with them will continue to improve.